Large User-Maintained Documentation?

SysKoll asks: "I am working for a company that has release several open source contributions. Our flagship product, often updated, has thousands of pages of documentation that are constantly revised to stay relevant. Right now, users who find a doc defect send an email, and the doc is updated both on the web site and in the updates, but it can take weeks. I am trying to convince my upper management that the way to go is to turn the doc web site into a wiki-style community site, where registered users can annotate pages directly between official revisions. Does anyone know a large set of web-published documentation that is annotated using this kind of user feedback?"