The idea is probably okay, but couldn't it possibly lead to the formation of a clique, which is usually detrimental to those left out? As I remember, my nose was always bent out of shape because I wasn't included within that group of stuck-up people who may have looked down at me if they saw me at all.
I think our Post of the Week
(or of the Whenever) is supposed to provide the individual with some glory. And instead of putting down those that haven't had one of theirs chosen, it is to provide them a bit of initiative to try to post better posts from the example.