There is an automatic job that deletes single-use tags after 6 months. No attempt is made at determining whether the tags are good and should remain, or whether the tags are a variant name of another tag and should be renamed or made synonyms. No attempt is made to retain tags that have proved their worth, for example with a tag wiki. There is no way to explicitly declare a tag as good. Even beta sites, where it is expected that the tag system is still evolving, are not exempt.. This job is not subject to any review, not even after the fact: one day the tags are there, the next day they're gone.
This has been shown to cause harm on Unix & Linux. Both our current untagged are incoming migrations, but I remember finding untagged questions in the past, that had were about a relatively obscure application and had obviously been tagged with the name of that application, which was exactly right and had to be redone. Untagged questions are only the tip of the iceberg: there is no way to know that a question had a tag deleted if it still has a non-deleted tag.
- turn off the job that deletes single-use tag, and provide a log of past deleted tags so that we can add them back where appropriate; or
- provide evidence that the deletions were beneficial to the site (I don't know what form the evidence could take other than a log of past deleted tags so that we can ascertain that the tags were indeed useless in a vast majority of cases).
badp has created a data explorer query that shows at-risk tags: tags that are used on a single question and have been around for at least 3 months. I reviewed the first 25:
- Proper names that should be tags no matter how many or how few occurrences there are: scrot easypeasy mozilla-prism jhbuild lxterminal meego mon ufw cclive openid cdm netscape iperf moin stress vyatta distcc
- Tag that was definitely useful but should have been written differently: linuix
- Concept tags that are somewhat useful, but not really critical (it would be useful to have them put for review, there might be a better applicable tag, but they should not be deleted silently): hardware-rec videoconferencing cyrillic pixel-art dock
- Meaningless or too vague tags that should just go away: repeat applet
So that's 18 strongly against, 6 weakly against and 2 in favor of the tag killer. Kill the tag killer!