A public wiki that covers
MacOsx programming topics, such as
ObjectiveCee and Cocoa (formerly
NextStep).
http://www.cocoadev.com/
The CocoaDev site was transferred to a new owner, who switched it to MediaWiki and disallowed anonymous contributions. That hasn't prevented most of the current activity on the site from being spam and reversions. Due to formatting differences, many of the code examples are unreadable. And I've noticed that the reversions are happening less frequently. A sad end to a once-essential resource.
2014-05-13:
CocoaDev is now implemented using
GitHub as a backend, but the content is still all 10 years old.
See also:
CocoaProgrammers