I draw your attention to posting.
There is, of course, no excerpt or tag wiki. It is attached to questions about "posting" on Twitter, Facebook, Facebook Social Plugin, Google Groups, Google+, Reddit, WordPress, between Twitter and Facebook, and Blogger.
Granted, as a verb it is a common activity on just about every social media site, bulletin board, and job board there is, but it doesn't convey any extra meaning beyond what the app-specific tags already do.
No one is an "expert" in posting who would come here looking for questions to answer.
Based on Shog9's criteria for burnination:
Does it describe the contents of the questions to which it is applied? and is it unambiguous?
Is the concept described even on-topic for the site?
Only insofar as one can "post" on many web sites and web apps.
Does the tag add any meaningful information to the post?
Does it mean the same thing in all common contexts?
I think it should be removed.