I came across this site and am wondering if there is a similar page for Mathematics or its sub-areas. Would be very nice if there is one such site which provides 'canonical' references for each sub area and preferably is editable like the Wikipedia system so that it reflects entire community's opinion and not just one person's choices (though the website mentioned above for string theory perhaps does not have this feature). Please provide a link to such a website if it exists.
As comments have pointed, Wikipedia is already good enough. On the other hand, I agree with the OP that the "String Theory Wiki" web-site provides an interesting form of collecting references and reviews. In my collection of links there is no such a site, and if it does not exist, it certainly should be created one day )))
Nevertheless, there are a few sites of a similar nature, that I'd like to list here as a partial contribution to the answer.
- The nLab, "This is a wiki-lab for collaborative work on Mathematics, Physics and Philosophy..."
- Tricki, "a Wiki-style site that is intended to develop into a large store of useful mathematical problem-solving techniques"
- Pr∞fWiki, "an online compendium of mathematical proofs"
- ExWiki, "exercises from various fields of mathematics and computer science"
Hopefully, there are other similar sites, and I'd be glad to hear about them too.