Wine has always been about being social. It is very rare that I don't share a bottle of wine with friends and I am always sharing recommendations with friends and colleagues.
Which is why it is so interesting that no one seems to have been able to put together a wine website or app that effectively uses social media AND has managed to attract enough people to make it truly social.
Corkbin does some things very well, when it comes to social media: it limits your comments about the wine to 120 characters, it integrates with your Twitter and Facebook account, and it lets you take a picture or choose from your library.
This makes the app very social media friendly, but on your terms. You aren't limited to to sharing with people on their site, though your Tweets and Facebook posts include links to their site.
It is probably a good thing that hey don't limit you to their site, because Corkbin suffers from the same problem that other social media wine apps share: lack of users. I live in a pretty tech-savvy area, but the closest user to me was 20 miles away.
As you can see, Corkbin users are pretty spread out, so relying solely on the app for social media sharing is not going to keep you connected unless you can provide a compelling reason for your friends to join you.