Somehow I missed Google Co-op. Here it's being used to define resoures health information. These collaborative bookmarking, path sharing projects are all the rage, though until now I've not found one that worked for me.
The Google Co-op project is intriguing of course, it's getting hard to keep up with all of their inventiveness -- is Google trying to advance The Singularity all by itself?
Needless to say, the memex had this feature. Vannevar Bush's 1945 prototype for the WWW+ involved the sharing of links, connections and paths in a collaborative development effort.
PS. Visiting my all-but-forgotten del.ici.us site I was intrigued to see the vanity feature -- an ancient link to Gordon's Tech under the old name is on a few other people's lists. I'll have to add all of my blogs and key pages there to see how many others have been found ... Clearly, I've not thought enough about these emergent collaboration sites ...