There are some particular questions that are asked at least once a day on Stack Overflow.
They're well-posed questions about trying to solve problems nobody should solve (great example: "How do I get this HTML DOM element with regular expressions?").
Obviously, all the interaction will be in the comments — since you have to be evil to actually answer such questions.
So, here is a nice idea: let the Ajax interface that suggests related questions be more aggressive if some particular phrases (in this case, the combination "regex, HTML, element") are typed. As in, display a highlighted sentence on top of the similar questions with some specific information (in this case, something along the lines of: "Are you going to ask how to parse HTML with regex? Don't. Click here instead.").
I think it would be a useful feature, from which both the asker's reputation and the quality of the posts would benefit.
Edit: I see there is a similar feature for questions that might be too subjective on Programmers, so implementation should be a breeze.