Hi, I'm Peter Maranci.
My primary use for LJ is as a place to bitch about having the fewest friends of anybody on LJ. :D
Seriously, I DO whine more than I should. But I've been working through the whole concept of popularity on LJ. In a sense, I view the LJ friend mechanism as an electronic version of high school. Who's friends with who? Did you friend me back? Are you making enough comments? Am I commenting enough on you? What did she say about him? Was that a secret? Should I make my journal friends-only? This is a private club!
The scary thing is that LJ can instantly put your brain back into high school mode, even if you (like me) have been out of high school for more than twenty years. It's kind of like moving back with your parents after college; suddenly you're a child again.
The trick, I think, is to either A) become massively popular on LJ, or B) find a way not to care. If you chose A), then it helps to be an attractive woman with exhibitionistic tendencies. If you chose B), I recommend Prozac and meditation.
Okay, I'll be serious. I use LJ to keep up with my friends - it's necessary, since I lost touch with them after marrying and moving - and as a place for political rants, notes about my little boy (I hope he'll read them some day), and my fiction - genre and non-.
I keep up with a few communities, but they're not at the top of my to-read list.
As for LJ and offline life, I've found that the people who comment most on my journal (and vice-versa) are the people that I met first in real life. I've run into a few people on LJ first, and expect to meet a few of them offline for the first time at the con, but the truth is that there's something missing from a purely electronic relationship...something difficult to define. Maybe that's something we can talk about.