as i work on my network in linkedin, and think about all the profiles i have to update - on oreillynet, livejournal, myspace, etc. I'm reminded that openid is the beginning of reversing the current profile situation. rather than starting from scratch with each new site and building a profile every time, a profile will be built in one place - preferrably a place you own completely. Each new site will ask for access to parts of the profile. the profile will become very detailed as its built up over years. each site contibutes to the profile with usage patterns for example. perhaps a user profile is too specific - a local data store of some sort. A windows registry for webapps. a webservices accessable warehouse of whatever data you want. google base comes to mind but it is not good at facilitating the edits of a user profile. a profile service sounds like a decent web 2.0 idea to build. start with openid.
user profiles in reverse