A while back when I changed and saved my signature it was changed on every post that I had made. I just now changed it, but nothing happened in existing posts. Was the previous behavior because I was a mod or has something else changed here at DaniWeb ?

We now cache signatures, but it should have been cleared out. Chalk it up to a bug that will be fixed in the future ... Currently working on priming the new version of vBulletin to go live, so hold any thoughts for now.