Pinterest is a social media tool that you need to be invited or request in invite to join. You can use your facebook sign in to log in once you get the invite. It is a fun interface that lets users bookmark favorite pages with photos.
Pinterest is also the best social media tool I have found to get your hubs out for more traffic. One of my hubs has circulated enough to get me just under 1000 views a day. This was a jump that happened just 3 days ago - it started with 150 views a day to a 1000 in just 3 days.