An interesting 'battle' if it can be seen that way.
For a marketer, this could be a useful test.
I still have twitter out in front on this "second screen"
For years, the "second-screen" leader has been Twitter, which positioned its chatty, 140-character message platform as the go-to place for viewers to discuss events as they happen, from presidential debates to the Academy Awards. But Facebook, the world's largest social network with 1.2 billion users - roughly five times the size of Twitter - is now making aggressive moves to get into the real-time conversation itself.
"Twitter is better at engaging in the real-time conversation," said Quinn Kilbury, the brand director for Newcastle Brown Ale. "But Facebook is catching up quickly - and you can't match their scale."Twitter and Facebook Going Head-to-Head Over Superbowl "Second Screen" [reuters.com]