This tag is for questions specific to down-votes, the community's way of telling peers that their content can be improved. Down-votes on meta site have different meanings.
As well as the standard "this question is unclear or not useful" and "this answer is not useful" meanings, on meta sites down-votes can also mean:
I don't agree with this suggestion/proposed solution
You haven't included any free hand circles (or arrows, or unicorns) on your screen shot
I can't reproduce the bug
So while the question or answer might be very clear and potentially useful, it is still entirely feasible that it will receive a down vote or two.
This tag is for questions which are specific to down-votes. For questions about the voting mechanics in general, use the voting tag. For questions about up-votes, use the up-votes tag.
Copied from: http://meta.stackexchange.com/tags/down-votes/info
