I used to physically write in private journals, but since discovering livejournal in 2002, it's taken on as a replacement and houses a lifetime of memories for me. It's a bit different because it can be read by others so it isn't completely private, but it still acts as a journal in that it allows me to mindlessly write what is on my mind or how my day went. I'm fairly certain I'm the only one who uses livejournal anymore, though Calliope and Pike will update once in a while. (This thread is really just a sad, desperate way to try to bring livejournal back. I won't let it die! I won't!)
Do you write in a journal or diary? If you don't currently, did you in the past?