  A social networking site is an on-line service that attracts a society of
subscribers and provides such users with a multiplicity of tools for
distribution personal data and creating subscribers generated content directed
to a given users interest and personal life. Operators of online social
networks are gradually giving out potentially sensitive information about users
and their relationships with advertisers, application developers, and
data-mining researchers. Some criminals too uses information gathered through
membership profile in social networks to break peoples PINs and passwords. In
this paper, we looked at the field structure of membership profiles in ten
popular social networking sites. We also analysed how private information can
easily be made public in such sites. At the end recommendations and
countermeasures were made on how to safe guard subscribers personal data.
