Back in 2002 when I first got online, I was very involved in an Irish traditional music discussion site and made some real life friends on there that I still have to this day.
Facebook and Live Journal are very different as someone has already said. Facebook is easier and more fun to use than MySpace. I'm still not fully involved with Live Journal. I have to remind myself to check friend's blogs or I forget. And if I forget I feel like I'm the only one who doesn't know what's going on with that individual. Maybe I also find it slightly stressful for some reason.
Also, as far as my own Live Journal page I'm not keeping one. I just feel like so much of what "goes on" with me is in my inner life if that makes sense, and I don't think anyone would be interested in that, or if they were I'd rather talk in person face to face about it. I guess I find it too personal. I may change my mind, though because in general, I love to write!