Researchers at Sheffield Hallam University have surveyed social network users, and discovered that you’re unlikely to make real, close friends, as reported on the Guardian
Despite the huge lists of contacts you can accumulate, the number of real, close friends is around the same as you’d have offline, and will tend to be people that you’ve met in real life.
Facebook, Myspace, Bebo et al can allow you to message 100s, or even 1000s of friends (In Robert Scoble’s case), but the actual number of close friends is likely to be about……five.
The reason is that humans tend to only really trust people after face-to-face interaction.

That figure may change as users become more trusting in connections made via social networking, but certainly it suggests that the social network would need to result in face-to-face meetings for real trust to be formed.

There’s also research that suggests those people who interact most successfully online are the same people who are most social-minded offline.

With all this is mind, it suggests that simply joining a social network and adding friends etc will simply maintain your existing contact list. The only way to use them to gain new contacts would be to go to the next level of participating in groups and discussion boards etc, utilising the now old school mechanisms of chat rooms and forums.

Certainly I’m a member of a huge range of social networking sites, but the only new friends who have become in any way close friends have come from two very focused forums, and one of those groups came together to attend a real life meeting.

The one reassuring thing is that it means those who put in time and effort will still gain more from social networking than those who just sign up to be part of the crowd…which is the way it should be.