When the CEO is referring to "partners" providing Wikia with free storage and bandwidth, I don't think he's referring to volunteers. They're probably other companies (ISPs? colo facilities?) who are giving their resources to Wikia in exchange for something else (a cut of the ad revenue? access to mailing lists of contributors?).

Right. That's clear because of "nondisclosure agreements". But he's giving them something in return, which is going to come from unpaid labor, I mean "user-generated".