As you can see the top bar includes a link to socl's top level (or "home"), a search/status hybrid box and to the right the profile picture as well as notifications. To the right, there is a vertical bar which at the moment is called "Video Parties" which is surprisingly well done and easy to join or start your own. So now you can have a YouTube party on the spot with potentially millions of people (assuming you wish to make it public, of course). At the moment, this right-hand vertical bar cannot be collapsed or stashed away, but I imagine they they'll add that option sometime in the future. Now, I think this is where Microsoft got it right: that status/search hybrid box I mentioned above is actually quite nifty. If you enter a search query (again, assuming you make it public), it will be posted for everyone to see and comment on, which can be a great social and research tool. For instance, you can find someone who's familiar in the subject or someone who can comment for a better search, find people with common searches and so forth. This is a very powerful feature that, if Microsoft plays it right, could be a boom for them.
Perhaps due to being launch day, but there are a good number of So.cl-ers online helping and engaging users, asking for feedback, making suggestions and so forth. I see this as a very positive move, which, I have to admit I did not see in Google+ even though I joined a few weeks after release. Another aspect that I see being better than both Facebook and Google+ is that by the way it works, you don't really need to follow or be followed. The information flow is such that you can just jump in and out of any conversation and then on to another with ease. So, even for the shy and introverted, So.cl offers good options.
Currently missing is the ability to create and manage groups/circles, but as per conversation with a So.cl-er it's a feature in their backlog.
Overall, I have to say that, for one, Microsoft got it right with So.cl. I'd tell FB and G+ about So.cl: ignore or dismiss at your own peril.
P.S.: I might write a more detailed review/overview after I use it for a while, so keep an eye out if it's something that you're interested in.