UPDATE: Since games has been burninated much of this Q has become moot so acceptance of the existing A closes this version for me. More here though.
Q When is facebook-games appropriate, on its own (~0 uses), as opposed to either facebook games† (~2 uses) or facebookfacebook-games (~5 uses) or one or more other tags instead?
Apparently facebook-games, along with several others, has in the past been merged into facebook (Merge [facebook-] into [facebook]).
There have been comments, such as (referring to archive):
This tag can't stand alone as the only tag on a question; it would always need another tag to give context. This seems to me to be a classic Meta tag.
which hark back to one of Jeff’s blogs where he wrote:
If the tag can’t work as the only tag on a question, it’s probably a meta-tag.
though the (extreme) examples he gave were beginner, subjective and best-practices (data may be another), which to me seem far removed from the likes of archive or games.
It seems that if a tag can “stand on its own” the chances are most Qs should only even have a single tag (maybe like facebook-friend-request-messages?) – or the Q is likely to be “too broad” (for covering more than a single topic) anyway.
Considering documents that was the topic of Merging [doc], [document] and [documents] tags. It can mean different things to different people (eg Word, PDF, a file in Google Documents, evidence for account recovery such as driving licence or passport (or images thereof, etc) and not so far actually applied in isolation (for a very small sample).
Related Q but inconclusive: Why are more general tags getting removed from questions?
Also related but not conclusive: In the context of Web Applications, which are the tags that are not specific to a web application that are not meta-tags?
† May only be temporary, but games does not exist at the moment (though it did when this Q was asked).
