Who's driving the Social Media bus in the Enterprise Space?

Interesting clip by Olivier Blanchard discussing the evolution of social media, as well as who's been jumping on the social media band wagon. Many agencies especially have been largely unsuccessfully because of lack of true understanding around how to do it in a scalable fashion. He observes after reading a post by @jowyang that the Big 4 firms are moving in as well but wondering how they intend to actually do this effectively. At the same time, how will they address issues of strategy, implementation, execution and measurement.