So I've set up a sort of generic "blog" area at my forums - one where only the original thread starter (and me, of course, as admin) can post in, just by modifying permissions. You start a thread, and it's yours and yours only. Sure, it doesn't have customization that some people's definition of a blog has, but for the people on my site, they don't really care to have all that. They just want a place to spill their guts, so to speak.
http://www.takemybagel.com/forums/forumdisplay.php?f=34