It is finally out! Together with Prof. Kitamura, I contributed one chapter. It examines the effects of Social Presence on the use of social media in learning. It organizes and integrates previous research, and also touches upon the recent use of tools like Twitter, albeit briefly.
The title is “The Role of Social Presence in Interactive Learning with Social Software.” I believe it is Chapter 19.

I would be very happy if you could take a look.