User Contributed Notes

Hi! I saw on your web pages that you have a feature you call "User Contributed Notes". It's these little annotations that user can add at the end of a web page (i.e. see http://www.php.net/manual/en/language.functions.php). We are looking for something similar right now to make our lives easier managing internal documents. It looks relatively simple, but still I'm very curious about how you approached this. I would be very glad if you could quickly describe how you did it, how it works for you, and maybe also if you had some problems, what YOU think about it etc. Thanks a lot for your advice in advance. patric