From the site:
"zeebox is social
Because zeebox knows what you and your friends are watching, you can all share. Think they'll enjoy what you're watching? Invite them to join you. Wonder what they're gawking at? Switch over and sneak a look. And you can all chat together, while you watch. Splutter over what Pat just said on EastEnders. Do your own commentary during the match. Share your disbelief about the score Craig just gave on Strictly. zeebox is even integrated with twitter, so you can tweet about what's going on..."