What is e-Learning 2.0?

Tony Karrer has a nice article on e-Learning 2.0. Tony writes: "What is e-Learning 2.0?" "is really not an easy question to answer, but let me take you through what I see as the cornerstones of eLearning 2.0. And let me apologize up front that I’m not trying to give any kind of formal definition. Instead, I’m trying to describe how I see eLearning 2.0 playing out in the short-term and medium-term for people in corporate eLearning."

My own "view" of e-Learning 2.0: The freeform application of Web 2.0 concepts for learning.
I think that we cannot have a precise definition of "e-Learning 2.0" unless we manage to define "Web 2.0" and more important "learning" in a precise way. However I believe that both "terms" are very troublesome and complex such that any sole definition will fail to define the whole landscape. So let´s concentrate on the concepts behind e-Learning 2.0 rather than trying to find a common definition for the same.