I stumbled across a review of the "post" tag edit which appears to be driven by this post and voted to reject it as lacking usage instructions, but while the definition appeared to be one accurate assessment, 2 more completely unrelated definitions leaped to mind immediately.
My gut reaction is that the tag should be binned as it is likely to be misused if it's used at all. What are your thoughts? Do we need the "post" tag on askubuntu and if so why?
No!
We don't want or need a post tag.
Why?
The term is clearly ambiguous and in my opinion unlikely to be a favourite. As it seems to me that tags are used to locate questions within ones area of expertise and there doesn't appear to be a common thread linking any of the questions utilizing the word post or any of it's derivatives I think that tag and anything similar to it is just providing an opportunity to dilute the usefulness of the tagging system (which I am against for reasons that are likely abundantly clear to those who use tags for their intended purpose).
I think that the confusion exist because the "post" tag does not have meaning or the possible meanings are misleading : are we talking about the act "to post" or the content ?
If we are talking about the act, a tag "posting" should be better and yes the question you mentioned fits in. It can be helpful to have a tag like this one.
If we are talking about the content then it automatically includes "Questions" and "Answers" tags (and their derivative) and lead to possible confusion and the post you stated does not fit in. As mentioned in comments a "posts" tag is then more accurate. However I don't think that kind of tag should exist due to the fact that the mere structure of this website avoids that kind of situation : questions are questions and answers are answers, we cannot have a situation that mix both or, if it's the case, does not rely on the content but other thing like style, formatting, ...
For me, in order to simplify :
Right now there is 350 results on the posting term ...
