![John Steiner](http://phibetaiota.net/wp-content/uploads/2011/03/John-Steiner.jpg)
Here's a TedX talk that was just released which shares more details on the concept of many-to-many: Gandhi 3.0 (slides here). For more context, Designing for Generosity speaks more about ServiceSpace values and its implications.
Also here some downsides: From Sharing Economy to Gift Ecology