I noticed in another question that work is underway to develop a palette for automatically uploading Mathematica images to StackExchange (and a "thank you" to those of you working on this--it will be very helpful and much appreciated). Is there a public repository for useful Mathematica code like that which has community-supported infrastructure similar to StackExchange (i.e., users can edit and comment about the code as well as vote on it)? I've occasionally found places where users upload code, but eventually these places become dumping grounds for junk and it becomes difficult to find the good stuff.
Right now, it seems that Github is a good option. Apart from full-fledged repositories, which are free and unlimited if the code is public, one can create gists, which can be used for smaller pieces of code one would like to share. Gists allow people to leave comments.
This choice has the following advantages:
What about just plain using a Wiki? That strikes me as the ideal. I think SE-style would work great because of the tag system.
Things like Github seem higher-threshold than necessary if we're just talking about relatively small snippets, plus searching through those systems is weirder, I think. (Also, it doesn't seem like Github actually supports Mathematica explicitly).