In recent years, micro-blogging Online Social Networks (OSNs), such as Twitter, have taken the world by storm, now boasting over 100 million subscribers. As an unparalleled stage for an enormous audience, they offer fast and reliable diffusion of pithy tweets to great multitudes of information-hungry and always-connected followers with short attention spans. At the same time, this appealing information gathering and dissemination paradigm prompts some important privacy concerns about relationships between tweeters, followers and interests of the latter. In this paper, we assess privacy in todays Twitter-like OSNs and describe an architecture and a trial implementation of a privacy-preserving service called Hummingbird a variant of Twitter that protects tweet contents, hashtags and follower interests from the (potentially) prying eyes of the central server. We argue that, although inherently limited by Twitters mission of scalable information dissemination, the attainable degree of privacy is valuable. We demonstrate, via a working prototype, that Hummingbirds additional costs are tolerably low. We also sketch out some viable enhancements that might offer even better privacy in the long term.
De Cristofaro, E.; Soriente, C.; Tsudik, G.; Williams, A. Tweeting with Hummingbird: privacy in large-scale micro-blogging OSNs. IEEE Data Engineering Bulletin. 2012 December; 34 (4): 93-100.