Encouraging parallel conversations during live events has been gathering pace recently. The Guardian have long had much success with their interactive minute-by-minute coverage of sport, and more recently live rolling news.
Even sweet old Radio 4 is getting in on the act; last night I heard them encouraging people to use the hashtag #r4riot and join in with one of their live shows.
But my favourite example recently is Riz Ahmed, an actor in Four Lions, tweeting live (simultweeting?) along with a screening of the film on TV. What a great way to spread the word and encouraging re-watching. It’s a bit like the audio commentaries you get as extras on DVD, but much more vital.