I think it should be possible to flag questions or answers that are spam.
To me it seems like a lot of people are spaming questions here just becaus they hope to get upvotes.
Also I already requested this feature a few weeks ago: When creating a new question musing should show you a selection of similar questions. Maybe you will already find a answer there so you don't have to publish a dublicated question. StackOverflow for example does the same.
Oh I like that similar question drop down idea
Obviously this question has been asked for but when I scrolled down a few days looking for one I didn't see it so I couldnt post my answer, hence I started a new one