Codeforces is a very nice site for competitive programming. It host online competitions from time to time, can serve as a online judge for solving problems, one can create groups and mesh up contest etc...

However, sometimes the Codeforces judge server can fail (for example, the current moment that I'm typing this post). Or maybe one discovered some other bugs in the website and would want to report it. In such conditions, an official bug/error report page would be very helpful.