One of the first social networking sites I signed-up a very long time ago was del.icio.us, a worldwide web bookmark (or shortcut) sharing site. Here I have been trying to keep track of all of our own websites, their pages and our pages on other sites that we belong to, though I now see that I have to update it quite a bit with these new listings for the social networking websites I have been joining.
Google also offers a bookmarking service, so that you can access your bookmarks anywhere. But Delicious goes a little further by allowing you to share your bookmarks with the rest of the world.
This is service is actually a fantastic idea and I think it will go far in the future as it has all sorts of possibilities for expansion. Some are already copying the idea (and even the format).