Jeff Jarvis has suggested tagging people (following up on all the talk about new Technorati tags).  I'm all for it.   (Of course, we do this in social situations all the time.  But it's good to cast light on the idea.) 

Tagging of objects (or people) allows the social level of the protocol stack to emerge.  It's not just about applications -- it's about people, groups, and metainformation.  Tagging doesn't diminish people, particularly if we have tags that you can write to as well as read.