My first contact with Internet was a remote shell into a proprietary Unix running on a Sun Sparc station using cu, it was more than 15 years ago. The Internet was not very accessible and it was the really the beginning of the World Wide Web. Now, the web (2.0 arf arf) is more social and clearly more accessible to a larger number of people. We were thinking that the World Wide Web was just a simple hypertext system to access remote services but know it's also socializing tool. In this context, I played a little bit with xfn (XHTML Friends Network), a simple mechanism to represent relationships between human using hyperlinks. I made a quick-and-dirty(tm) xfn module for Oddmuse to automate in the markup the creation of such relation :
[[person:URL|Text|relationship]] [[person:http://www.stallman.org/|Richard M. Stallman|met muse]]
Now what's the use of that ? An example, the 'me' relationship is available and permits to show that you have control over the remote link. It helps to better represent the same person across different web services. Another example, it's linking different social networks by the relationship of the people. That helps indexer and crawler to better classify search results regarding the specific group of linked (or non-linked) people. xfn is very simple (just the rel attribute) compared to FOAF, it's easier to maintain xfn link in any blog or wiki software than FOAF (IMHO). I'm sure that more good ideas mixing tagging and relationships will come in the following months… but I just say nothing.