  In the last decade, Online Social Networks (OSNs) have taken the world by
storm. They range from superficial to professional, from focused to
general-purpose, and, from free-form to highly structured. Numerous people have
multiple accounts within the same OSN and even more people have an account on
more than one OSN. Since all OSNs involve some amount of user input, often in
written form, it is natural to consider whether multiple incarnations of the
same person in various OSNs can be effectively correlated or linked. One
intuitive means of linking accounts is by using stylometric analysis.
  This paper reports on (what we believe to be) the first trilateral
large-scale stylometric OSN linkability study. Its outcome has important
implications for OSN privacy. The study is trilateral since it involves three
OSNs with very different missions: (1) Yelp, known primarily for its
user-contributed reviews of various venues, e.g, dining and entertainment, (2)
Twitter, popular for its pithy general-purpose micro-blogging style, and (3)
Flickr, used exclusively for posting and labeling (describing) photographs. As
our somewhat surprising results indicate, stylometric linkability of accounts
across these heterogeneous OSNs is both viable and quite effective. The main
take-away of this work is that, despite OSN heterogeneity, it is very
challenging for one person to maintain privacy across multiple active accounts
on different OSNs.
