Oh man, I used to. I re-read it years later and it was sooo embarassing! My entries were like "today I saw <insert name of crush here> he's sooooo hot, omg." and they went on. Still, I'm glad I kept them because it was interesting to re-read little things that happened to me I had forgotten about. I think I'd like to start one up again, but keep it more informative and less personal- so incase it falls into the wrong hands- I won't have to worry.
PS. I threw out my old journals after re-reading them! :-P