On Thu, Feb 5, 2015 at 6:53 PM, James Forrester jforrester@wikimedia.org wrote:
I know for one that they're frequently used for analytical purposes to track behaviour and performance. The AF ones aren't, but AbuseFilter's use of tags is (numerically) niche.
I don't know that I'd call 3410388 out of 9051234 (37.68%) on enwiki "numerically niche". And if we exclude the 2330952 HHVM tags from the total, it's up to 50.57%. Other wikis, perhaps, have less AF use and more VE.
But as long as whatever "analytical purpose" that added the tag continues to respond to the ListDefinedTags hook, the tag can't be deleted by this mechanism unless it's explicitly allowed by the ChangeTagCanDelete hook. So excessive concern over those being deleted seems like it's just that, excessive.