I think the PHP guys figured out the best possible way to manage documentation. Each page of the PHP docs outlines how a function is used; the page is followed by a list of commentaries from PHP programmers, which are selected and edited by the PHP staff. Then, when the documentation is revised, the best of the comments are analyzed and incorporated into the new docs.

I have a local HD copy of the PHP docs that are missing the commentary, and let me tell you, it's nowhere near as useful. Public documentation is teh shizznit.