There's the fun aspect of finding people from school and seeing that they turned out exactly like the train wreck everyone knew they would be but you can go and click through their pics and actually see it happen sometimes.
I still refuse to get a Facebook acct despite the constant prodding from my family. On rare occasions I'll use my wife's acct to check out something one of my sisters post.
I used to go on there a lot, but got tired of reading everybody's issues. Now I go on there every couple weeks, and thats mainly to check what the local beer store has coming in.