Coincidentally I just set up a response that uses 418 I'm a teapot about an hour ago. I really wanted 422 Unprocessable Entity, but werkzeug doesn't implement that (and for some reason instead implements 418 I'm a teapot).
It's not even as useful as the Wikipedia list as the main page fails to specify which codes are from WebDAV, etc., and it even copies some made-up non-RFC codes without including the caveats.
Part of my job is user support and a frequent problem is users not sure what a server error means, when explaining I like to provide sources for explanations I give. I don't like linking to the RFCs or wikipedia because they can be overwhelming/confusing for people who aren't particularly competent with technology. The original aim for this site was to have explanations in layman terms that anyone could understand and then also the wikipedia and RFC explanations, unfortunately I found that I am not very good at explaining... in the end it didn't turn out how I wanted but I figure there might be some value in it existing for some people -- I can still use it as a reference when providing user support, but it won't be as useful as hoped.
What user would ever care what a status code means? For users, there are two status codes: "200 OK" and "^200 Not OK and the webmaster has been notified"
I like the idea of adding that, I could also include httpstat.us in the same way, here's an example of how I think I'll do it (under code references): http://httpstatus.es/101
Use the whitespace to the right of the status codes to display their explanations, rather than linking to a new page; it would be easier to browse this way.
I especially like that the entries put front and center the degree to which the official RFCs are actually respected by browsers. That content is all (obviously) in Wikipedia and other sources, but usually buried in a subsection.
Which ones specifically? I had to keep the micro-explanations very short so they only give a very very basic over-view, but the full page explanations should be more than suitable as they're a combination of the Wikipedia explanation and the official IETF explanation (from the RFCs).
Well, for 304 the explaination is "this and all future requests should redirect to given URI", which is just wrong. Simply "Not modified" would be better.
http://en.wikipedia.org/wiki/List_of_HTTP_status_codes
On a side note, I need to start using 418 "I'm a teapot" more often.