Protection of private information on social networks (SNs) has become a serious and important topic since social network sites became popular and widely adopted worldwide. Usually people want their personal information to be known only by a small group of people including close friends and families. But sometimes they willingly accept to give some particular information about themselves to individuals which are neither a friend nor an acquaintance. Each SN has different purposes and people subscribe many of them. However, public information available on these sites reveals many aspects of user’s identity. In this work, it is shown that public information can be used to detect the different accounts of the same individual. This study is performed on two popular social media sites: Twitter and Facebook. Public attributes of the profiles such as real name, user name and status updates (tweets and posts) are used for comparing profiles on two SNs. Different data mining algorithms are compared for matching profiles. Also relationship between text similarity and total term counts of status updates is analyzed. Results show that simple features like real names, user names and status updates have high similarity between the accounts of the same users and these features can be used to detect profiles of the same user on different SNs. Also the more status updates a user posts on Facebook the more he will likely be detected by the matching schema. Thus, public information can be exploited to pose a threat to the privacy of the people on the Internet.