Microsoft might be trying to catch up on Facebook although they publicly state that the site So.cl was never intended to be a rival to Mark Zuckerberg's social network.
The site is primarily aimed at students as Facebook was when it started and has a retro look. Microsoft already partnered with New York University, Syracuse and with the University of Washington.
Students are presented a visual way to share links. These are then displayed as a visual montage to their friends. So.cl also offers a feature seen on Google+: real time sharing of videos.