Here was idea about forum for Codeforces — which probably would not be implemented (at least soon) since probably administration have no resources for it.

And then I thought to myself:

But CF already have a cool API. If only we can use it also for Authentication "via CF"! Then surely creating such forums (or other add-on resources) could be done by any 3-rd party enthusiasts!

User only need to click link Login via Codeforces from such resource (and login to CF if needed) — and then the resource will be told by CF about identity of this user, his nickname, color, profile page etc.

This will allow anyone to create custom supplementary resources which could be easily used by CF users!

BTW: this is far easier to implement than the forum! :)