There must be some costs. Who is paying for all this?

P2PU is largely run by volunteers, however we have also gotten seed funding to cover some basic costs from both the Hewlett Foundation, and the Shuttleworth Foundation. The project is also being incubated at the University of California at Irvine. Thanks to ever cheaper web-hosting there are few direct costs involved in setting up an online learning community. Of course it also takes a lot of time and effort to make this happen, which we have put in as volunteers.