When I see someone I know, who's on LJ, we rarely talk about those things that end up here. I mean, if I post that my Java class is going well (it is), I'm not going to really be telling other LJers this fleshside. The smalltalk that ends up here is removed from my life.
Livejournal is a big part of my life. I check it every break at work, several times a night when at home. If I'm out and come back, I check LJ. Sounds pretty bad, I know, but this is my information nexus. Most things about me end up here, save the sordid little details about sexual fetishes. Though I'm thinking that I may LJ cut a few "How-to" guides.
My interactions with everyone I know is colored by what happens on LJ. The information that is shared here is on some level, the bud behind most things, and the things LJ doesn't cause, end up posted here.