In LiveJournal, I can post public, friends-only, or private posts.
If I do a private post, then only I can read it. In the several months that I've had a LiveJournal, I've posted just one private post.
Today I changed it to friends-only. It's here. Oddly, I'm scared.
EDIT: June 2003: this post, and the one to which it refers, and others, are now public.