Today, one can find from the web vast amount of information about an individual. Specifically, such information can be classified into two categories, virtual and real-world identities. This paper addresses a novel problem of linking these two types of identities based on information publicly available on the web. We start by studying how one can link virtual identities (i.e., user profiles) at Twitter with real-world identities at Whitepages.com (containing personal information such as name, age, relatives, etc.).
We demonstrate that a substantial portion (at least 0.17%) of Twitter users in the U.S. can indeed be potentially linked to their real-world identities through information available at Whitepages.com, revealing sensitive personal data. We discuss the implications of such identity linkages on both individual privacy and law enforcement, and also point out the future studies required in this topic.