A description and wiki was added to artifacts recently. The tag has nine questions as of this writing.
Is this tag actually useful? Can one become an expert in artifacts, or should the tag go the way of similar meta tags like bugs?
My stance would be "no," the artifacts tag isn't useful in either it's current form or any more-generalized form. In both cases the tag is describing what is being observed in the question, not the problem attempting to be solved in the question.
Even when localized specifically to rendering artifacts, it's very possible for two artifacts to be caused by two very different rendering issues such that it's unlikely that there exist a significant body of users out in the real world with dedicated experience fixing all forms of potential undesired rendering behavior... and thus nobody would every put the tag on their "highlight these tags" list. Certainly, at least, the people who would are also the people who'd use existing tags like graphical-effects or some tag more specific to the graphics subdomain involved.
If we were to remove the graphics focus from the tag description, it would only make the problem worse (then it would cover audio artifacts as well, for example).
Consequently I think we should treat this tag like we treat bugs and blacklist it.
Personally I think the tag should continue to live on, maybe renamed to "graphical-artifact". The thing is, artifacts are not really any type of "effects" at least not desirable ones; So I doubt anyone will tag his question.
If I were to ask a question about those kind of graphical issues, I think this tag would be the best option we had indicating we are actually asking about solving a bug!
Looking at the search results for artifact also shows we actually do have a lot of questions about the issue, but people don't like to tag their question for some reason, which makes going through similar question a bit harder.