The Role of the Internet in Facilitating Violent Extremism and Terrorism: Suggestions for Progressing Research

  • Ryan ScrivensEmail author
  • Paul Gill
  • Maura Conway
Living reference work entry


Many researchers, practitioners, and policy-makers continue to raise questions about the role of the Internet in facilitating violent extremism and terrorism. A surge in research on this issue notwithstanding, relatively few empirically grounded analyses are yet available. This chapter provides researchers with five key suggestions for progressing knowledge on the role of the Internet in facilitating violent extremism and terrorism so that we may be better placed to determine the significance of online content and activity in the latter going forward. These five suggestions relate to (1) collecting primary data across multiple types of populations; (2) making archives of violent extremist online content accessible for use by researchers and on user-friendly platforms; (3) outreaching beyond terrorism studies to become acquainted with, for example, the Internet studies literature and engaging in interdisciplinary research with, for example, computer scientists; (4) including former extremists in research projects, either as study participants or project collaborators; and (5) drawing connections between the on- and offline worlds of violent extremists.


Violent extremism Terrorism Radicalization Internet Social media 


Like most of us, violent extremists often leave a digital footprint behind. Notable examples include Anders Breivik, the Norwegian far-right terrorist who was a registered member of a white supremacy web forum (Bartlett and Littler 2011); Dylann Roof, who allegedly posted messages on a white power website (Southern Poverty Law Center 2015); and Aaron Driver, who showed outright support for the so-called “Islamic State” (IS) on several social media platforms (Amarasingam 2016). In such cases, questions often surround the impact of the offenders’ consumption of and networking around violent extremist online content in their uptake of extremist ideology and/or their decision to engage in violent extremism and terrorism.

These questions sit at the top of the priority list for many researchers, practitioners, and policy-makers (Conway 2016). At recent specialized terrorism conferences – including, for example, the 2018 VOX-Pol Conference on “Violent Extremism, Terrorism, and the Internet: Present and Future Trends” – the nexus between the on- and offline worlds of violent extremists dominates much of the discussion (for more information on the conference, visit At workshops hosted by law enforcement, the defense community, and similar agencies – such as the Swedish Defence Research Agency’s Seminar Day on “Violent Extremism: Methods, Tools and Techniques for Detecting and Analyzing Violent Extremism” – focus much of their attention on gaining insight into how the online discussions, behaviors, and actions of violent extremists can spill over into the offline realm (for more information on the workshop, visit Similarly, at summits and roundtable discussions, social media companies – including Facebook with their Dangerous Organizations Summit – display concern about their platforms facilitating radical communications which, in a number of instances, have translated into violent offline activity. Others, including policy-makers, are concerned that high and increasing levels of always-on Internet access and the production and wide dissemination of large amounts of violent extremist content online may have violent radicalizing effects (Berger and Strathearn 2013; Carter et al. 2014; Edwards and Gribbon 2013; Gray and Head 2009; Stenersen 2008). This is, after all, a primary goal of the producers of such content.

The abovementioned concerns and interests notwithstanding, little is empirically known about the Internet’s role in the facilitation of violent extremism and terrorism (Gill et al. 2017).

Determining the significance of the role of the Internet in contemporary extremism and terrorism is not the goal of this chapter, however; it has a narrower remit. It provides researchers with five key suggestions for progressing knowledge on the role of the Internet in facilitating violent extremism and terrorism so that we may be better placed to determine the significance of the Internet’s role in the latter going forward. In what follows, we provide five suggestions that relate to (1) collecting primary data across multiple types of populations; (2) making archives of violent extremist online content accessible for use by researchers and on user-friendly platforms; (3) outreaching beyond terrorism studies to become acquainted with, for example, the Internet studies literature and engaging in interdisciplinary research with, for example, computer scientists; (4) including former extremists in research projects, either as study participants or project collaborators; and (5) drawing connections between the on- and offline worlds of violent extremists. This chapter also draws from and builds on Conway’s (2016) six suggestions for progressing research on the intersections of violent extremism and terrorism and the Internet.

Recommendation 1: Collecting Primary Data Across Multiple Types of Populations

Reviews of the terrorism research literature regularly highlight the paucity of original data that inform analyses (Schmid and Jongman 1988; Silke 2001, 2004). In his most recent review of the literature, Silke (2013) noted: “[O]ne feels that a great deal more needs to be done before research is consistently building on past work rather than rehashing old data” (p. 34). Resultantly, as Silke argues, terrorism research has lagged behind analogous fields. The most recent review, however, offers a more positive outlook. Schuurman (2018) analyzed over 3,000 articles published in leading terrorism-specific journals between 2007 and 2016 and found that over half used some form of primary sources. The Society for Terrorism Research (2018) also described the data revolution in terrorism studies as a transition from a data shortage to one of “sufficiency and perhaps even excess” (p. 1).

A systematic review of the scientific knowledge base of factors associated with engagement in terrorism shows a similar improvement in empiricism over time (Desmarais et al. 2017). However, this increase has not been uniform across the field. Empirical studies examining engagement in violent extremism and terrorism demonstrates the field tends to focus on individual-level risk factors (e.g., sociodemographic characteristics, criminal history, religion and spirituality, work and education, relationship status, mental health), personal experiences, attitudes and beliefs, environmental factors, and individual motives. Only 18 studies that met Desmarais et al.’s (2017) stringent systematic review criteria empirically examined the radicalization process. Fewer still, presumably, examined the online radicalization process.

Indeed, Hassan et al. (2018) conducted a systematic review specifically focused on the relationship between the impact of extremist online content and violent radicalization. Eleven studies fit their eligibility criteria. The included quantitative studies involved two cross-sectional analyses with data derived from surveys (Pauwels and Schils 2016) and online discussion forums (Wojcieszak 2010), retrospective studies of those who committed acts of terrorism (Gill et al. 2017) and engaged with radicalizing materials on Twitter (Magdy et al. 2016), and two with pre-/post-measures conducted in a lab setting (Lee and Leets 2002; Rieger et al. 2013). The included qualitative studies involved focus groups that directly exposed participants to propaganda material (Baines et al. 2010), interviews and ethnographic work with those previously exposed to radicalizing material as well as former extremists (Drevon 2016; Koehler 2014b; Sikorskaya 2017; von Behr et al. 2013), and case studies including one examining the computer hard drives of convicted terrorists (Drevon 2016; von Behr et al. 2013). The studies also looked at how exposure to online materials produced changes in emotion (Baines et al. 2010; Sikorskaya 2017), attitudes (Drevon 2016; Koehler 2014b; Lee and Leets 2002; Magdy et al. 2016; Rieger et al. 2013; von Behr et al. 2013; Wojcieszak 2010) and behavior (Drevon 2016; Gill et al. 2017; Pauwels and Schils 2016).

Other empirical studies, however, not included in Hassan et al.’s (2018) systematic review have involved examinations of what media were found on the computers of convicted terrorists (Holbrook 2017, 2019), the volume of media consumed by terrorists (Capellan 2015; Gill et al. 2014; Gruenewald et al. 2013; Horgan et al. 2016; Porter and Kebbell 2011), the interaction between the individual consuming the propaganda and the content of the propaganda itself (Bouzar and Martin 2016), the impact of exposure upon attitudinal affinity with an extremist cause (Ilardi 2013; Kleinmann 2012; Koehler 2014b; Turpin-Petrosino 2002), the impact of exposure upon mobilization to terrorist engagement (Bazex and Mensat 2016; Klausen et al. 2016; Reeser 2011; Riaz and Parvez 2018), the specific manifestations of radicalizing narratives that prompted engagement in terrorism (Abbas and Yigit 2016; Özeren et al. 2014; Sieckelinck et al. 2017; van San 2018; Wojcieszak 2009), and the impact of exposure upon mobilization to terrorist behavior (Böckler et al. 2015; Holbrook and Taylor 2017). Many of these studies involved interviews, surveys, and/or access to police files.

The potential to collect primary data (be it, open-, closed- or researcher-generated data) across multiple types of populations (e.g., general public, those with attitudinal affinity, those with radicalized beliefs, and those who committed terrorism) is clearly evident. The emerging evidence base is also pretty clear. Those who are radicalized and/or commit acts of terrorism have generally been exposed to radicalizing content. Exposure to this content leads to affective, emotional, and behavioral change at each stage of the process. Of course, some of these studies have relatively small sample sizes and are only focused on specific types of terrorists or geographical contexts. The key now is to replicate and build upon this preliminary evidence to give us a sense of not just whether exposure to ideological content in the online environment causes violent extremism but also how, in what contexts, and for whom?

Is “exposure” sufficient whether it is in the virtual or physical world? Does it work differently for different people in different contexts? To unpick the specificity of the “online” environment, exposure to other materials offline has to be incorporated into research designs. The only study of its type is Turpin-Petrosino (2002) who conducted 567 surveys with secondary school- and university-level students. The surveys centered around exposure to hate group propaganda and individual attitudes toward these groups. Respondents reported six different types of contact: print material contact (4%), word-of-mouth contact (3.7%), US mail contact (3.4%), local cable television contact (2.6%), Internet contact (1.8%), and phone contact (1.4%). Levels of support for the ideology also differed across these exposure types. Forty percent of those who received Internet contact self-reported supporting either neo-Nazi skinhead or Ku Klux Klan (KKK) ideology. Of the six exposure types, the Internet was the third most prolific source in changing people’s attitudes – behind word-of-mouth contact and phone contact. Given the large innovations in the immersiveness of the online space since this study was conducted, more replications are necessary.

Recommendation 2: Making Archives of Violent Extremist Online Content Accessible for Researchers

The increased attention from researchers to violent extremism and terrorism may be due, in part, to sophisticated, relatively user-friendly, virtual, and open-source platforms containing qualitative and/or quantitative data on terrorism events, groups, and individuals (Bowie 2018; Chermak et al. 2012). These range from academic, think tank, and independent databases to commercial and government databases (Bowie 2018). Notable leaders include the National Consortium for the Study of Terrorism and Responses to Terrorism (START) and their Global Terrorism Database (GTD), Profiles of Individual Radicalization in the United States (PIRUS), Profiles of Perpetrators of Terrorism in the United States (PPT-US), Terrorist and Extremist Organizations (TEO) Database, and United States Extremist Crime Database (ECDB); the Pew Research Center’s Data Surveys on Terrorism; the Terrorism Research and Analysis Consortium (TRAC) Database; the Southern Poverty Law Center’s Extremist Files Database; and the Jihadology online portal (for a recent list of terrorism databases and datasets, see Bowie 2018).

These sources provide unprecedented opportunity and ability to address previously unexplorable questions as well as assess and re-evaluate old research questions with new resources and new research methods. Despite these recent developments, the ability to build, maintain, and make accessible archives of violent extremist online content for use by researchers lags behind parallel fields of study utilizing similar online material (Conway 2016).

Providing researchers with access to nontraditional data sources, especially open-source intelligence and social media data, will, without a doubt, transform the future understanding of violent extremism and terrorism in general (LaFree and Freilich 2018) and the role of the Internet in the facilitation of violent extremism and terrorism in particular (Conway 2016). Surprisingly, only a small number of individuals have contributed to this initiative. The University of Arizona’s Dark Web Forum Portal, for example, collected and made available the content of 28 jihadi forums comprising nearly 13 million messages (for more information on the Dark Web Forum Portal, visit The Dark Crawler (TDC) database, housed at Simon Fraser University (SFU) in Canada, includes – but is not limited to – over 11 million posts from the most conspicuous right-wing extremist forum, Stormfront; over 8 million posts that include Islamist content; as well as over 49 million posts drawn from 11 extreme right-wing subreddits. All are available to users for research upon request (for more information on TDC, visit Yet not only are these excellent databases few and far between, these two resources have not been widely used by researchers (some notable exceptions include Chen 2012; Macnair and Frank 2018; Scrivens et al. 2017, 2018).

What, then, explains the lack of uptake? And why, compared to those who developed the GTD, for example, are so few researchers developing similar databases for the purpose of sharing violent extremist online content with others in the field? For the former, it may be the case that such data sources are much less known than the GTD, for example. For the latter, we suggest it is because most researchers in terrorism studies are social scientists and thus do not have the necessary skills to easily collect, store, and analyze truly large quantities of online data. Further, a lack of standards related to online research, including the absence of methodological rigor related to sampling and concerns about data saturation, plays a role. There are at least four ways to overcome this obstacle however: (1) learn how to undertake basic online data collection and analysis ourselves; (2) build data archives and develop bespoke tools; (3) use commercial data brokers; and (4) work with computer scientists. Collaborating with colleagues from other disciplines, including computer science, is addressed in the next section, so we will briefly address points 1–3 here.

It is possible for social scientists to learn how to use basic online data collection and analysis tools, especially freely available open-source software accompanied by clear “How To” documentation and online tutorials. Gephi data visualization software is one such accessible tool. This option is made more attractive when researchers have the opportunity to learn how to use these tools in dedicated “real-world” tutorials and workshops, preferably tailored for social scientists (see, for example, the University of Amsterdam’s Digital Methods Initiative at Another option, as we have noted above, is to build, maintain, and make accessible archives of violent extremist online content for use by researchers. Wide take-up of these resources will most likely require the availability of easy-to-use analysis tools alongside data in an integrated service, however.

The responsibility for sharing accessible content should not only be placed on researchers. Social media companies should take active steps in assisting in this regard. This, however, is not a simple undertaking. To illustrate, Twitter has allowed researchers to extract data from their platform using computer programs, but Facebook recently locked down their data following the Cambridge Analytica scandal, making it increasingly difficult for researchers to extract and, by extension, conduct large-scale analyses of Facebook’s content (see Bastos and Walker 2018). This is problematic for those working in terrorism studies since Facebook is by far the most popular social networking site in the world (Statista 2018) and widely exploited by violent extremist movements of different ideological standpoints (Awan 2017; Ekman 2018; Johnson et al. 2016; Nouri et al. 2017; Stier et al. 2017; Weimann 2010). While we acknowledge that social media companies must balance the privacy of its users with national security, there requires the development of new partnerships with researchers for the purposes of making online content accessible for scientific purposes. We are seeing some signs of these next steps with, as an example, the implementation of “Social Science One,” an initiative being developed at Harvard University’s Institute for Quantitative Social Science in which academics from around the world are working with Facebook to identify valuable datasets that will be made available to researchers through a peer-review process (Reuell 2018).

We further suggest that, in developing industry-academic partnerships in terrorism studies, researchers and social media companies should avoid operating in silos and, by extension, hoarding data. This tactic has historically been the way in which many experts “do business” (see King and Persily 2018). Not sharing information is particularly concerning in this realm given the oftentimes scattered, fragmented nature of data. To illustrate, one stakeholder may have one critical piece of information about the online activity of a particular violent extremist group, for example, while another stakeholder may have another piece of information. Developing open lines of communication and sharing information with researchers will undeniably transform our understanding of the role of the Internet in the facilitation of violent extremism and terrorism.

In addition to sharing data among key stakeholders, those working in this area should make a concerted effort to triangulate data across databases and datasets. Taking a lead in this respect are, for example, Chermak and Holt, who have triangulated data between the ECDB and the PIRUS databases, testing whether theories of social control and social learning shed light on the on- and offline pathways to hate and extremist violence. This provided multiple observational points to explore the similarities and differences across offenders’ background, attitudes, and behavior (for more information on this project, visit Perhaps equally valuable here would be for researchers to merge such databases (and others) with databases that include violent extremist online content, such as the abovementioned Dark Web Forum Portal and TDC database, and develop a central database in which various online platforms that violent extremists and terrorists have been known to frequent can be made available in one space. This would place researchers in a better position to explore, for example, whether consumption of violent extremist online content lead directly to violent acts occurring that would not have occurred if the Internet did not exist.

Recommendation 3: Outreaching Beyond Terrorism Studies and Engaging in Interdisciplinary Research

The original interest of most of those currently researching the intersections of violent extremism and the Internet is the former, rather than the latter. This is easily amendable by, for example, exposing ourselves to new literatures beyond terrorism studies and/or direct outreach to colleagues in other disciplines. A literature that researchers in our field could usefully familiarize themselves with is Internet studies, while disciplines that we could perhaps most usefully collaborate with colleagues from include computational linguistics, computer science, information systems, and statistics.

It is pertinent to ask about media and communication studies in general and Internet studies, in particular what Jackson (2012) asked about conflict analysis and peace research and its relationship to terrorism studies. He inquired:

How is it that the “known” knowledge of the causes and resolution of violent political conflict (including conflicts where terrorism was present), which has accumulated from decades of conflict analysis and peace research, among others, remains largely “unknown” within the terrorism studies field? Why is it that within terrorism studies research continues apace on questions related to terrorism’s causes and effective responses without reference to the key scholars and existing studies of peace and conflict studies? (p. 12)

Reformulating Jackson’s (2012) question then: “How is it that knowledge of the intersections of media and conflict (including conflicts where terrorism was present), which has accumulated from decades of media and communication research, among others, remains largely ‘unknown’ within the terrorism studies field? Why is it that within terrorism studies research there has been a surge of research on questions related to terrorism and the Internet, especially social media, without reference to the key scholars and existing studies of media and communication research generally and Internet studies particularly?” A ready answer to this question, which basically queries our lack of knowledge of other social science research, is much more difficult to supply than, say, a convincing answer to the question of why collaboration between social scientists and computer scientists or statisticians is not more prevalent.

We want to emphasize here the necessity of drawing from Internet studies to enrich research on violent online extremism and terrorism. There is a large and increasing body of work done by Internet researchers that is germane to this particular sphere. Internet researchers have, for example, generated a significant amount of work on credibility and trust online, none of which deals directly with violent extremism or terrorism but is nonetheless straightforwardly relevant in that it engages deeply with questions like how credibility is built online, how credibility is lost online, and so on (Bowen and Bowen 2015; Bryce and Fraser 2014; Naquin and Paulson 2003; Nissenbaum 2001; Wang and Emurian 2005). Hegghammer’s (2014) analysis of jihadi online forums is clearly enriched by his drawing from this specific literature, but few other terrorism researchers have followed his lead. Another pertinent area of Internet research is the strongly consistent finding that discussion forums and other online spaces are generally dominated by a few “super contributors” (e.g., Ducol 2012; Leimeister and Krcmar 2005; Silverstone 2005). Berger and Morgan (2015) made a similar finding for IS-related Twitter activity (i.e., of the network of 40,000+ user accounts analyzed, c. 1,500–3,000 were prolific tweeters) but omitted discussion of the way in which this is at least partially explainable by previous research on non-extremist online environments and thus is not unique to IS. Having said this, “The ISIS Twitter Census” is an excellent example of a beneficial collaborative relationship between an extremism researcher and a technologist/data scientist, which did the important job of answering some of the what questions regarding IS’s Twitter presence.

Truly interdisciplinary research is easier said than done. Collaborating with colleagues from other disciplines, including computational linguistics and computer science, is distinctly different than drawing from other social science fields like communication studies or Internet studies. It was suggested above that social scientists educate ourselves in the use of basic online data collection and analysis tools. However, for more sophisticated analyses, we need to work with those who not only have knowledge of the available tools and their deployment but can tailor these further. This is not a one-way relationship with computer scientists benefiting their social science colleagues in the absence of benefit to themselves. The best outcomes are obtained by computer scientists collaborating with domain experts – in this case those with knowledge of the ideologies prevalent within and the day-to-day workings of online extremism and terrorism. Increased collaboration between social scientists, especially terrorism studies scholars, and computer scientists is the most pressing need, but there are a host of other colleagues we could doubtless also benefit from collaborating with (e.g., criminology, psychology, law, etc.).

Recommendation 4: Including Former Extremists in Research Projects

A growing industry (i.e., research centers, consultancy groups, and government departments) is tackling the problem of violent extremism, both in the “real world” and in cyberspace. Known in academic and government circles as “countering violent extremism” (CVE), it is largely designed to divert individuals from radicalization to violence using “soft” approaches rather than purely securitized and/or criminal justice responses (Harris-Hogan et al. 2015). Commonly, researchers, practitioners, and policy-makers draw from the insights of former violent extremists and terrorists – colloquially known as “formers.” Some researchers, however, have raised concerns about including formers in CVE campaigns, ranging from discussions about their reliability and credibility to questions about whether their inclusion could raise concerns in the public sphere (see RAND Corporation 2017).

By conducting in-depth interviews with former extremists, researchers have gained insight into processes of radicalization to violent extremism (Koehler 2014a, b; Simi et al. 2016), factors that minimize radicalization to mass casualty violence (Simi and Windisch 2018), and greater comprehension of processes of disengagement from violent extremism (Barrelle 2015; Bubolz and Simi 2015; Horgan et al. 2017; Simi et al. 2017; Windisch et al. 2017). Additionally, researchers generally agree that formers can usefully advise on the development and leveraging of counter-narratives due to their firsthand experience in extremist movements. By extension, they are also more likely to be perceived as credible voices by those who may be attracted to violent extremist groups or radical ideologies (Bjørgo and Horgan 2008; Braddock and Horgan 2016; Briggs and Feve 2013; Jacobson 2010; Macnair and Frank 2017).

In recent years, social media, tech companies, and think tanks in particular have been quick to turn to formers to assist in the development of online CVE campaigns. The “Redirect Method” is one illustration. It combines Google’s search advertising algorithms (i.e., AdWord technology) and YouTube’s video platform to identify those who are searching for violent extremist content on Google and then expose them to counter-narratives (for more information on the Redirect Method, visit Former extremists have been involved in this process on at least two fronts: (1) a small group of formers developed the list of targeted search terms, and (2) many of the counter-narratives that have been offered to the target audience feature the stories of formers (see Helmus and Klein 2018).

Other online CVE initiatives that have gained attention in recent years include “Extreme Dialogue,” which broadcasts an array of emotive films on Twitter, Facebook, and YouTube, some of which include stories from formers. These films attempt to dispel extremist myths and encourage others to actively consider subjective experiences (Reynolds and Tuck 2016). In addition, formers have served as intervention providers on online CVE campaigns, including the Institute for Strategic Dialogue’s (ISD) “One to One” pilot project, in which formers directly messaged an array of individuals Facebook identified as right-wing extremists or Islamists (Davey et al. 2018; Frenett and Dow 2014). Lastly, social media and tech companies (such as Google, Facebook, and YouTube), in partnership with think tanks (e.g., ISD) and CVE companies (e.g., Moonshot CVE), collaborate with former extremists to develop and structure new responses to violent extremism online. Here, formers have been drawn upon to enhance the abovementioned stakeholders’ knowledge on ways to counter violent online extremism, ranging from formers being asked to identify and provide insight into content of interest (e.g., hate symbols, keywords, and terms) to providing tech companies with insight into what counter-narratives may be effective. All such efforts, although on the surface promising, still require a full evaluation of effect size and direction, mechanisms (e.g., an understanding of how these efforts make an effect), moderators (e.g., the contexts in which they work best), implementation burdens, and cost (Bowers et al. 2018).

Regardless of the abovementioned developments and despite an increased focus on the intersection of violent extremism, terrorism, and the Internet (e.g., Gill et al. 2017; Freilich and Chermak 2012; Gerstenfeld et al. 2003; Holt 2012), scholars who are working in the field of violent online political extremism have been much slower to bring formers to the table. An exhaustive search using dedicated academic research databases produced only two studies that interviewed former extremists about their Internet usage when they were involved in extremism. Koehler (2014b), for example, conducted in-depth interviews with German former right-wing extremists, with the focus of the study on the role of the Internet in individual radicalization processes. Overall, the author found that the Internet was the most important driving factors in participants’ individual radicalization processes, as it provided members with a space in which they could learn skills that were necessary to access online extremist groups. Koehler also found that the Internet was a central hub for extreme right-wing groups, recruiters, and strategies to influence the radical views and subsequent behavior of others online. Sieckelinck et al. (2017), during their interviews with 34 former extremists (extreme right and jihadist) in Denmark and the Netherlands on their life courses into and out of extremism, also highlighted the key catalytic role of exposure to propaganda online. Following the 9/11 attacks, an individual in their study decided to search online for information about the war in Afghanistan. Viewing this content, the participant claimed, was a key push factor within their radicalization process.

Also worth mentioning here are a small number of studies that interviewed current extremists on their media consumption and radicalization process. Ilardi (2013), for example, conducted interviews with seven Canadian jihadists and found that, in combination with close personal relationships with other extremists, the exposure to extremist literature and media was “decisive in instilling in interviewees the type of beliefs that would lead them to identify with the world of radical Islam” (p. 728). Özeren et al. (2014), in their examination of the recruitment strategies of the Kurdistan Workers’ Party (PKK) and Kurdistan Communities Union (KCK) via face-to-face interviews with 42 members, depicted the organizations’ various media outlets, including websites, online radio, and television as key to the organization’s recruitment strategy. Lastly, Bazex and Mensat (2016) conducted in-depth interviews with 12 young French jihadists who fought in Syria and were, at the time of the study, in custody for terrorist-related offenses. The authors, who also had access to investigation files, noted several individual risk factors including delinquent behaviors, setbacks in personal loving relationships, school failure, variability in religious beliefs, and a lack of protective factors. The study also demonstrated that consumption of radical material on the Internet played a fundamental role in the young jihadists’ decisions to go to Syria.

Indeed, these studies provide valuable insight into the Internet’s role in facilitating violent extremism and terrorism, but this area of research remains in its infancy. Having said this, in progressing our understanding of the role of the Internet in facilitating violent extremism and terrorism, formers who have experience with and insight into the online dynamics of violent extremist movements will play a critical role in future research, whether they serve as participants or act as collaborators on research projects. In particular, in furthering our understanding of the interplay between the Internet and violent extremism and terrorism, researchers should incorporate former extremists into their research strategies by interviewing them about their Internet usage and activities when they were involved in violent extremism.

Questions may include those that relate to:
  1. 1.

    The types of online platforms they frequented when they were in an extremist group or movement (e.g., websites, discussion forums, blogs, social media sites, etc.)

  2. 2.

    Online activities they engaged in during their time in an extremist group or movement (e.g., radical content consumption, propagandizing, recruitment, networking, planning attacks, etc.)

  3. 3.

    The extent to which they depended on the Internet to connect and communicate with other adherents when they were in an extremist group or movement

  4. 4.

    Their online identity versus offline identity when they were in an extremist group or movement

  5. 5.

    The extent to which their online contacts – versus their in-person contacts – influenced their radical belief system during their time in a group or movement

  6. 6.

    The extent to which their online contacts – versus their in-person contacts – influenced their radical behavior and offline activities during their time in a group or movement


Asking former extremists such questions should provide researchers with firsthand accounts of and insider’s perspectives into a number of key issues that academics continue to be concerned with, including how the online discussions, behaviors, and actions of violent extremists and terrorists can spill over into the offline realm. Within this context, Scrivens et al. (2018) suggest that researchers can assess the potential confluence or divergence of on- and offline behavior by interviewing former extremists who were (a) active only online, (b) active only offline, and (c) active across both online and off. Comparing their posting behaviors over time may provide much-needed insight into how online behaviors may translate into the offline world.

For formers who are collaborators with researchers on academic projects, researchers may consider including them in decision-making processes, especially at the front end of a project. Formers, for example, can help make decisions about the types of online spaces that should be the focus of a study (e.g., web forums vs. social media platforms) and/or the online content that should be the focus of analysis (e.g., discussions about certain adversary groups, martyrs, religious figures, etc.). At the analysis phase, formers can provide researchers with an in-depth understanding of the online material and inner workings of particular violent extremist groups, for example. We caution researchers in this regard though. This type of collaboration requires formers who are willing to work with researchers, as well as a level of trust between the two. At the onset of a project, then, both parties should discuss their expectations from the collaboration, especially those that relate to protecting the identity of the former(s). Certainly, formers, out of fear of repercussions by members of their former extremist group (or other groups), may not want to have a public profile, and researchers must therefore protect their identities if formers so choose (Briggs and Feve 2013; RAND Corporation 2017). Overcoming these obstacles, and many others not mentioned here (for more information on the challenges of working with formers, see RAND Corporation 2017), will be essential for the development of these collaborations.

Recommendation 5: Drawing Connections Between the On- and Offline Worlds of Violent Extremists

Online radicalization to violence does not happen in a vacuum. Even in those rare cases where all exposures to radicalizing narratives and interactions with other co-ideologues happen in the online space, the individual is still influenced by a crystallization of motives, needs, and drivers from the offline world. In fact, the adoption of extreme beliefs is often a response to other problems in the offline world (see Gill 2015).

To date, we know very little about how this interacts empirically. What little evidence does exist suggests that we should not conceive radicalization as an offline versus online dichotomy. Von Behr et al. (2013), for example, examined primary data of 15 radicalized individuals, nine of whom were convicted under the UK terrorism legislation. The study made use of interviews (with police and the individuals themselves), trial records, and computer registries. One key finding suggested the Internet is “not a substitute for in-person meetings but, rather, complements in-person communication” (p. xii).

Additionally, Gill and Corner (2015) looked at the behavioral underpinnings of lone-actor terrorists since 1990. The results suggested that while the number of lone-actor terrorist plots remained stable over time, the growth in the Internet has altered their means of radicalization and attack learning. The Internet therefore acts as a substitute for other factors such as intelligence gathering and attack planning, not necessarily a force enabler. Furthermore, according to Gill and Corner, there was a significant positive correlation between those who virtually interacted with co-ideologues and those who interacted with co-ideologues face-to-face.

Building on Gill and Corner (2015), Gill et al. (2017) examined the online behaviors of 223 convicted UK-based terrorists. Those who learned online were 4.39 times more likely than those who did not learn online to have experienced non-virtual network activity and 3.17 times more likely to have experienced non-virtual place interaction. Of those who plotted an attack, the individuals who attended training camps were also significantly more likely than those who did not attend training camps to have learned online. Additionally, the evidence also suggested that communicating with co-ideologues online was significantly more likely to have been accompanied by face-to-face interactions with non-violent co-ideologues. Those who communicated online were 3.89 times more likely to have experienced non-virtual network activity and 3.17 times more likely to have experienced non-virtual place interaction. Of those who plotted an attack, the individuals who attended training camps were also significantly more likely to have communicated online. This may be due to the compartmentalization of tasks noted by Gill (2015). For example, individuals tended to learn about a specific necessary task online (e.g., bomb-making) but then found a different instrumentalization in their offline interactions with co-ideologues (e.g., the justification of bombing a particular target).

Finally, Holbrook and Taylor (2017) focused on pre-arrest media usage of five case studies of UK-based terrorist who were thwarted and convicted of offenses under terrorism legislation. The cases consist of a lone dyad, a socially active lone actor, an isolated lone actor, a connected lone actor, and a close-knit, hierarchical group. Holbrook and Taylor address a gap in the literature by focusing on behaviors that occurred before subjects were arrested, rather than relying on a post-arrest narrative that may have been skewed by self-justification. In all five cases, a belief pathway precipitated any operational action where all actors were active participants in the consumption, discussion, and distribution of extremist materials before any physical involvement in attack planning. Subjects consumed a diverse range of media across a number of platforms and interacted online in chatrooms as well as offline by copying compact discs (CDs) of extremist content for one another.

While much has been learned from these few studies about the link between the on- and offline worlds of violent extremists and terrorism, researchers – in addition to the suggestions described above – should draw from mixed method approaches to further our understanding of the intersection of violent extremism, terrorism, and the Internet. Researchers, for example, could combine online data with offline data in an effort to triangulate the offline experiences of violent extremists with their online presentation of self, language, and behavior. This, among other research strategies, would provide researchers with a more in-depth understanding of the interactions between the on- and offline worlds of violent extremists.


In closing, and by way of full disclosure, we believe the Internet is playing significant and diverse roles in contemporary violent extremism and terrorism. Rapoport (2002) argues that structural factors are very important in terms of influencing the various waves of terrorism identified by him. Historically, new communication technologies (e.g., mass circulation newspapers, radio, audio cassettes, and television) have been shown to be particularly influential and have a history of transforming terrorism; the Internet is unlikely to be any different. Given the resources, in terms of both time and money they are inputting to online campaigns, a diversity of contemporary violent extremists certainly thinks it’s having an impact too. Some of the anecdotal evidence is also compelling. Taking just IS into account, online outreach to young women has resulted in an influx of “jihadi brides” to Syria. Similar online calls for families to migrate to the “caliphate” have seen an uptick in family groups departing various countries, and a spate of previously uncommon types of terrorist attacks (e.g., running down people with cars and knifings) appear to correlate with online calls for these types of attacks to be undertaken. None of this is sufficient of course; what needs to be supplied is theoretically sound, empirically verifiable, social science research detailing – we hesitate to use the word “proving” in a social science context, especially this social science context – the role of the Internet in contemporary radicalization processes.

The earliest piece of analysis on violent extremism and the Internet appeared in 1985 (see Anti-Defamation League 1985), but the vast bulk only began to be produced in the 2000s, with a significant uptick since c. 2010 and a particular spike since the height of IS. Research in this area is thus not long underway, and so, of course, there are many what and why questions still to be asked and answered. The nature of the Internet means that it changes very fast. It is thus quite difficult to effectively research the Internet and its workings over time. Direct audience research is also problematic because of the nature of violent extremist and terrorist online content, which presents problems for undertaking the kinds of experiments that are standard in other areas of Internet audience research as it would require introducing subjects to online content with allegedly radicalizing effects and, in fact, almost certainly necessitate exposing youth and young adults to distressing levels of violence. Progressing research in this area is thus not easy. It is not impossible either however. There are, of course, a whole host of issues that were not possible to address in this chapter, such as widening the range of types of violent online extremism being studied beyond violent jihadis; engaging in more comparative research, not just across ideologies but also groups, countries, languages, and social media platforms; deepening our analyses to include interviewing and virtual ethnographic approaches; and paying more attention to gender as a factor in violent online extremism (for more on these, see Conway 2016). Regardless, the purpose of this chapter was to make five practical suggestions for progressing research on the role of the Internet in contemporary violent extremism and terrorism with, perhaps, the side effect of also kick-starting discussion of colleagues’ additional or preferred steps in this regard.


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Copyright information

© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.School of Criminal JusticeMichigan State UniversityEast LansingUSA
  2. 2.Department of Security and Crime ScienceUniversity College LondonLondonUK
  3. 3.School of Law and GovernmentDublin City UniversityDublinIreland

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