We believe that the similarity of phone numbers is caused by the convenience of this
information. Users want their friends to be able to reach them. Users may have decided that
home addresses are not needed for convenience and could be considered more personal. In
general, it has been shown that Internet users are willing to reveal personal preferences online
such as favorite books and movies; however they are hesitant to share their personal contact
information online (Cranor et al. 1999). Our results for Facebook demonstrate this fact.
Information relating to contact information is provided less than 45%, but all other types of
information that we looked at are provided more often than 60% of the time.