All participants to Wikimedia projects are currently working for free; Everyone is a volunteer.
Indeed, Jimbo is *more* than a volunteer, since he not only giving so much heart and time for the project, but he has also been giving some of his revenues to sustain the project for more than 3 years now.
However, many contributors are indeed giving a lot of their time, among which the developers. Should we or should we not envision to pay them, or to reward them for their hard work ? What do you think ?