When we check the Community Ideas, we now often find duplicate (or very similar) ideas. They are usually merged by the community administrators after some time, but this process is currently done in a cumbersome way (afaik), being the ideas most of the times commented by someone as being duplicated with some other idea.
It would be nice to harness the power of this awesome community, in actually reporting the duplicate ideas to the administrators (as opposed to writing a comment and hoping for it to be read), by having for instance an option "Report as duplicate" together with an auto-complete where the duplicate idea could be chosen. Then the administrators would receive a periodic report, allowing them to more easily know which ideas are duplicated and merge them, improving the quality and voting of Ideas.
Hope this one is not actually duplicated :)