Tim O'Reilly writes:
one of the secrets of success in Web 2.0 is to harness self-interest, not volunteerism, in a natural "architecture of participation."
We must keep this in mind as we build MediaVolunteer. Some people may want to volunteer selflessly, but many more will want to point at something and say "I did that", or get a certificate of their involvement, or have us fill out a form for community service...