It's a litle annoying sure - but I think when you're online you don't have the benefit of voice tone, facial ex<x>pressions and body language, so lol sort of covers that for things that might otherwise be misconstrued as serious or b1tchy.
It's like, I use LOL all the time..like, you know..LOL!!
Yes I agree, its overused
Good point, never thought of that before but now that you mention it your right