I have noticed that old contests sometimes have a very abbreviated editorial (if any) with proofs omitted or just an author's solution without description. I think it would be nice to have a way to the community to step in and provide / improve existing editorials. For example by having wiki pages or allowing linking user's post to an existing problem (without beeing original problem setter or admin). Of course, that may lead to all problems with abuse but people here are way more reasonable than an ordinary forum.

What do you think? Maybe that already exists and I am missing something?