Balancing Email and Social Tool use?

Luis Suarez of IBM has been treating us with some very interesting post on using less (corporate) email and more social tools. I've pointed to several of those posts before and commented on several of his post.
Basically he wants to stop using corporate email (except for confidential matters) and move all communication to social tools. This is a neat experiment.
However I was one of the questioners that wondered how the time he spends/spent on email is compared to social tools. I understand his experiment is not about that, but I'm not asking it to be skeptic. I think it's a relevant question.
Of course shifting communication from email to social tools is cool, better and more productive/efficient (in the long run). But it does have to be in balance (or doesn't it?).
For instance, I can send back an email in a couple of seconds to someone with whom I share a certain context. I can leave out all the details when I reply to him/her. But when I want to answer him/her via my blog I also have to think about all the other people that don't share that context. Because they don't, they'll be frustrated when they read my post. Writing such a post (instead of an email) would take more of my time. Or am I missing something?
Also in this post Luis states that "Content is no longer king". I've read it before, but don't get the point. And I'm not sure it's true either. I'd say content is still key, the media type isn't (anymore).