Information Retrieval

, Volume 15, Issue 3–4, pp 296–331 | Cite as

A deniable and efficient question and answer service over ad hoc social networks

  • Simon Fleming
  • Dan Chalmers
  • Ian WakemanEmail author
Information Retrieval for Social Media


When people are connected together over ad hoc social networks, it is possible to ask questions and retrieve answers using the wisdom of the crowd. However, locating a suitable candidate for answering a specific unique question within larger ad hoc groups is non-trivial, especially if we wish to respect the privacy of users by providing deniability. All members of the network wish to source the best possible answers from the network, while at the same time controlling the levels of attention required to generate them by the collective group of individuals and/or the time taken to read all the answers. Conventional expert retrieval approaches rank users for a given query in a centralised indexing process, associating users with material they have previously published. Such an approach is antithetical to privacy, so we have looked to distribute the routing of questions and answers, converting the indexing process into one of building a forwarding table. Starting from the simple operation of flooding the question to everyone, we compare a number of different routing options, where decisions must be made based on past performance and exploitation of the knowledge of our immediate neighbours. We focus on fully decentralised protocols using ant-inspired tactics to route questions towards members of the network who may be able to answer them well. Simultaneously, privacy concerns are acknowledged by allowing both question asking and answering to be plausibly deniable. We have found that via our routing method, it is possible to improve answer quality and also reduce the total amount of user attention required to generate those answers.


Expert retrieval Ad hoc social networks Expert search Stigmergy Privacy via plausible deniability Real time Q&A routing 



This work was supported by the Engineering and Physical Sciences Research Council, grant EP/F064330/1. We would like to thank Des Watson and the anonymous reviewers for their help in polishing this article.


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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  1. 1.School of InformaticsUniversity of SussexBrightonUK

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