I started using Notational Velocity (http://notational.net) years ago and still use it pretty effectively. I try to label things and keep them searchable. It's the repository for anything I might need to remember.

To be honest, I don't really review them but I do occasionally have to search back through them to answer questions like, "what was that feature I promised on that phone call?"

1 out of 10 notes ends up being useful, the others are pretty much trash.