Yes, I think this is a meta tag based on the [criteria of Jeff Atwood](http://meta.superuser.com/questions/1376/is-data-an-useful-tag-do-we-need-it-what-should-we-do) and [his blog post](http://blog.stackoverflow.com/2010/08/the-death-of-meta-tags/):

> 1) could you have a question with ONLY this tag  

I don't think so, [missing-files] and [data-loss] are better than [missing], [data] and [loss].

> 2) does the tag commonly mean different things to different people

Yes, people are left to wonder what is missing.

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As [disappeared] is just a synonym tag to [missing] it is also a meta tag.