Major upgrade in store for vBulletin in a few weeks. Wow, are there going to be a lot of new features...I'm not sure how many hacks I have installed will be affected but the tagging system is soon to be built in.
If interested read here: vBulletin 3.7 First Look! - vBulletin Community Forum
If interested read here: vBulletin 3.7 First Look! - vBulletin Community Forum