Social Networks might not be secure according to a new study by email research specialist, emedia, which you can read about here.
"….Nearly two thirds (62%) of networking sites users say they are worried about the safety of their personal data held on these sites, reveals a survey conducted by email research specialists, emedia, using its RapidResearch service. The concern is so high that almost one third of users (31%) have already entered false information about themselves to protect their identity."
In many cases, members don't use or understand the security settings contained within a social network (like Facebook) and give out more details about themselves than they need to.