Add the ability to mark an answer as incorrect.
The amount of traffic a question gets once it has one or two "answers" goes down dramatically. This creates a situation where, if the first two or three answers you get are bogus, you're unlikely to ever (or within a reasonable time) get a correct answer. People just stop looking at the question because they assume their odds of answering it and being rewarded are low.
Why not have the ability to mark answers as "wrong" or "incorrect"? This could then be reflected in the feeds, and would let people looking for questions to answer know that the question is still worth their time.
EDIT - Grace Note had some good points that I'd like to address in the question.
- "Downvoting should solve this" - The reality that I've observed is that answers that miss the mark often still get upvoted. After explaining why they don't address the question, voters are unlikely to come back and change their vote.
- "Unanswered feed also solves this" - The unanswered feed is littered with posts that have been abandoned. Points hunters do not find it to be an optimal use of their time.
My observation is that people hunting points look at the feeds, and heavily prioritize questions that have received no answers yet. The traffic flow seems to go down by an order of magnitude for every answer left, regardless of acceptance or votes.
My proposal would give question askers the opportunity to express the fact that not only are they still paying attention to the question, but they're actively reviewing answers and seeking a correct one to reward.