One of the most overly used tags in the site is error. In almost every case, there are many other tags which are far more descriptive.
All 303 questions using that tag aside, I believe the tag should be purged and blacklisted. I would like everyone else's opinion, however this is a very strong recommendation.
freezeto this too.
datecould probably be included as well... but there's a thousand of these tags that need purging with fire, so...