Simpy is a social bookmarking service. With Simpy, you can save, tag and search your own bookmarks and notes or browse and search other users' links and tags. You can be open and share your links with others, or keep them private.
Simpy also helps you find like-minded people, discover new and interesting sites, publish your bookmarks, detect and eliminate link-rot, etc.

I think that Simpy desperately needs an "add to friends" button in the relevant places, Instead, it has places where you can sign up for feeds, look at other people's bookmarks, start groups, search, etc. Not at all intuitive. It looks that they're trying to resurrect many of the bad features of the very messed up Yahoo! groups and other portal functions.