With so many questions that have valid answers, but they aren't marked as such, could we get the ability to "vote to mark as answer" or some similar functionality?
There is a similar functionality, just upvote the correct answer. This answer will then bubble to the top. On StackExchange, the definition of “unanswered” is “questions with no upvoted or accepted answers”.
Only the questioner can really say if one of the posts answers their question. Not all questioners bother to take the trouble unfortunately, but that can't be helped.
This topic has come up many, many, times. While I agree that the current work-around is OK, I don't think this really addresses the root issue we have here, which is too much noise on the site and frustrated users.
We seem to be proposing a treatment for the symptom, rather than the root issue. What we need is another mechanism to improve the thread quality/searchability/readability in an organic way.
I would certainly advocate a vote to mark as answer.
The community is a good mechanism for determining what entails a solution.
We allow community edits to a question - so I just can't get behind the rationale that "only the OP knows if something is a solution". This is a red herring.
If the community understands the question enough to make edits that improve the clarity and quality of the original question, then it reasons that the same people would have to have a clear understanding what constitutes the best answer, otherwise, why are we allowing reviewed edits?