From the Discussion section: This work shows that it is clearly possible to tie digital identities together and, most likely, to real identities in many

From the Discussion section: This work shows that it is clearly possible to tie digital identities together and, most likely, to real identities in many cases only using ubiquitous usernames. We also showed that, even though users are free to change their usernames at will, they do not do it frequently and, when they do, it is in a predictable way. Our technique might then be used as an additional tool when investigating online crime. It is however also subject to abuse and could result in breaches in privacy. Advertisers could automatically build online profiles of users with high accuracy and minimum effort, without the consent of the users involved. From the Conclusion section: We extend this technique to cope with profiles that are linked but have different usernames and tie our problem to the well known problem of record linkage. All the methods we tried have high precision in linking username couples that belong to the same users. Ultimately we show a new class of profiling techniques that can be exploited to link together and abuse the public information stored on online social networks and web services in general.