What do upvotes and downvotes mean on Meta? Does it mean "We should not discuss this," or "Good question, the answer is 'no'"?
My interpretation of down-votes on questions:
The bug should not be fixed.
This is not an important bug (is by design, cannot be reproduced, minor, etc.).
The feature request should be denied.
discussion requesting something (close/protect/lock/delete a post, merging tags, etc.):
The request should be denied.
discussion about an issue where
the author presents his own views in the question:
This issue is not important/badly posed/otherwise bad, or
I disagree with the view.
the author does not present his own views in the question:
This issue is not important/badly posed/otherwise bad.
Of course, ideally, people who downvote anything will leave a comment to explain why/suggest improvement, or upvote an existing such comment.
The meta tradition is that a down-vote can simply mean "I do not agree with this proposal" or simply "I do not want this implemented." It's not necessarily a reflection on the quality of the question.
Part of meta's purpose is to field
feature-requests. Higher-voted feature requests raise their awareness and are given more consideration. Hence, If you want to see a feature implemented, vote it up. If you don't want to see a feature implemented, vote it down.
As it follows, a similar justification applies to general discussions or anything else posed to meta.
What does it mean to agree with a question? (Upvote this if you agree with me!)
In meta.SO, an upvote means "I agree" and a downvote means "I disagree".
I am adding this answer because the question came up again recently and, while much of what I wrote is a little redundant, there is an aspect of the culture of MSE which I think is worth discussing.
In general, a vote on the main site indicates that a post is poorly researched or of low quality. On Meta, votes should, for the most part, be interpreted differently. There appears to be a broad and informal understanding that a downvote Meta indicates that the voter disagrees with the sentiment expressed in a post, and that an upvote indicates agreement.
There is no "official" policy on the meaning of votes on Meta. However, the help page titled "What is "meta"? How does it work?" has the following to say:
Voting is different on Meta.
Like normal Stack Exchange sites, Meta allows members to vote on questions and answers. For most posts, votes reflect the perceived usefulness: well-written, well-reasoned, well-researched posts tend to get more attention and more upvotes. Highly-voted and frequently-linked posts may become part of the community-curated FAQ or codified as part of the site’s Help pages.
Unlike normal Stack Exchange sites, Meta invites the community to discuss, debate and propose changes to the way the community itself behaves, as well as how the software itself works. On posts tagged feature-request, voting indicates agreement or disagreement with the proposed change rather than just the quality or usefulness of the post itself.
There is also some commentary on the SE Meta:
On Meta, however, many questions revolve around matters of taste (e.g. the HW question). When voting on answers to such questions, I want to be able to push down the suggestions that I disagree with and promote the ones that I think are correct. But I don't want to hurt people's reputation by doing so.
Downvoting on Meta isn't really saying "your answer is stupid and wrong"; it's more like "I prefer we do it the other way". The whole site is basically meant to discuss matters of social preference, etiquette, do's and dont's, etc.
Finally, I think that it is worth repeating the following: the notion that "votes on meta are different" (including the idea that they indicate agreement or disagreement) is an aspect of the culture of Meta. This is not an official policy, but is, instead, an emergent property of social interactions on Meta.