Pete Cashmore writes about the Internet Address Book, a venture from the Dutch Fresheads. You can find me here, but I can't enter all the profilepages I have at various services throughout the web. This service is more symptomatic for a specific need (managing your online identity), the implementation itself is not so interesting. Jason Kolb's six posts on this topic are very interesting, he comes to a different solution for the same problem. As do for example ClaimID and PeopleAggregator I wrote about earlier.
"The Internet Address Book, which launched this week, is a new service from the Netherlands that brings together all your online identities in one place - social networking URLs, instant messaging IDs and web addresses. You create an account, then add your IDs from Fotolog, Facebook, Webshots, Gaia Online, Photobucket and the usual suspects (including MySpace, of course). There’s also a live search that finds people across multiple social networks - the results seem pretty good, but it works best when the user is already registered. They’re also working on a “wanted” section, where you can list people you’re looking for. What’s more, you can add people you know to your contacts."