What you do rather than what you use
It is possible to get too carried away with trying to describe, explain and define what 2 is and try artificially to exclude certain things because they aren’t 2 enough. The process of looking too hard at it could make it disappear.
The essence of 2 is social and involves participation, collaboration and DIY. Cavemen did it, animals do it (think of pack hunters for example), we do it in our everyday lives all the time and it can even take place in some meetings.
What marks out the current wave of 2 is that it involves the virtual and mediation by ICT – Facebook for example attempts to do virtually what we do with physical presence – meet, share things, chat etc.
The important thing for me is seeing 2 in whatever flavour whether wholly virtual or wholly physical or any degree in the middle.
Teaching with role play and simulation with no technology at all is as valid as teaching using second life for example. The crucial thing is to engage the students and use methods which connect with them – today this often means on-line environments like facebook, youtube, blogs etc.