In this course we have a forum for each exercise that we get in which students may ask questions.
It seem that a lot of student tend to ask questions that lead to overheading the exercise. They especially tend to ask weather this or that needs to be implemented.
I figured that there should be a way to moderate these unneeded questions... if say for example a given number of students that take the course think the question is an overheading one they may vote to delete it and it will be removed from the forum so that the staff doesen't need to address the tedious question.
I am not absolutely sure what you mean by overheading. I think one issue is setting up the expectations for communication (see this site for ideas and resources http://www.atimod.com/e-moderating/5stage.shtml).
If you have a forum where students can ask about some things e.g.what the client wants but not others e.g. whether their current solution is 'right', then it's important to clarify these ground rules in the forum (and reinforce them too). So the first time an inappropriate question is answered, explain why you won't answer it, the next time ignore it.
IMHO, the student voting solution could create a lot of hassle and distraction, but it might work in your setting - who knows?