phpWebNotes is a page annotation system for manuals and how-to documents modelled after php.net. It is a php based solution to letting users contribute their own comments to a document. This project was originally conceived to help people who maintain technical help documents and how-tos. These web docs most often benefit from having user added footnotes. Visit the site to see a sample demo. You can also see a real sample at: http://mantisbt.sourceforge/manual/