Also agreed. Yes, some real life friends are also on my LJ friends page. I have some people I know in real life who use LJ that aren't. Because, like anyone I meet on LJ and don't add to said friends list, I don't find what they write to be interesting enough for me to follow them on a regular basis.

ETA: I should also mention that's my primary problem with LJ's use of the term "friends list". You write things that interest me. That does not a friendship make. Yes, it gives us something with which to start a possible friendship, but we're not friends just because one of us hit the add button.