Supposedly mediating relationships through a computer makes it easier for the socially challenged. Not necessarily so. For one thing, there is more pressure now to post pictures of yourself as you really look. For some of us, that's sure to subtract social points.
But the biggest problem is that it's a new type of social interaction, with new rules. Or rather, with the rules in formation, constantly changing. (Rules are always present; people always have expectations.)
For instance, "friending" is not the same thing as "befriending." But there's no rule as to where to draw the line to avoid being cold and unpopular, or, at the other extreme, foolish and unsafe.
For now, my compromise is to limit my Facebook "friends" to family and real friends (which includes not only close friends, but also coworkers and some people I know through long correspondence).