It's called So.cl and it's borrowing from Google Plus, Facebook, Pinterest, Flipboard, and many other successful social and sharing sites. Microsoft says it's primarily for students (as Facebook once was), but it's open to all. I decided to check it out for myself…
You can sign in using either Windows Live or Facebook, and it is automatically connected to those accounts. That is an interesting move, and one that indicates that So.cl is not actually aiming to eliminate Facebook, but to compliment it in some way.
The site suggests that you subscribe to things you like so that when others search for, share, and/or post those things, the results will be in your feed. I don't think this is executed perfectly but out of all of the Big Ideas within so.cl, it seems like by far the best one. I actually would like an option to subscribe to all public "sloths" posts on facebook.
Navigating the site is pretty far from intuitive -- for example, when trying to find interesting people I could follow (since no one I actually know is there yet), it automatically suggests ten popular people with no option to either see more, or check out their profiles without following them. There's also no way to import a profile photo -- you have to either have a Microsoft Live photo, or give it an existing URL.
The site is set up primarily to connect searching directly to social sharing. Here's what happens when you search for "buzzfeed," for example. Immediate short list of top, general results, with the option to select and share. It seems like this feature would be more useful if it was more linked to timeliness, like a twitter search.
