That's an interesting thought, because I think Yahoo was the provider for a bunch of stuff like @sbcglobal.net email addresses, and who knows what others.
I should go on and change my password, I think it's the same one I set up probably back in 1997-1998 timeframe. Based on the name of a restaurant that a group of us went out to that was pretty tasty.
edit: yep, still the same one. I remember being annoyed that I couldn't get my initials as a username, I think they required at least 5 characters.