The point of the Netflix prize was to improve something Netflix already understood well and was getting diminishing returns for its research dollar. The Netflix Prize was able to attract serious interest from legitimate academics and engineers because the problem was refined to the point where it was legitimately very hard.
ZipCar doesn't even offer one-way car trips. I'm sure it could do them with adjustments to inventory, management, and pricing. Traditional car rentals are evidence there is a model that works. But ZipCar needs start one-way car trips, much less get to the point where it has reached diminishing returns on its research investment, before it can expect worthwhile contributions from crowd sourcing.
ZipCar doesn't even offer one-way car trips. I'm sure it could do them with adjustments to inventory, management, and pricing. Traditional car rentals are evidence there is a model that works. But ZipCar needs start one-way car trips, much less get to the point where it has reached diminishing returns on its research investment, before it can expect worthwhile contributions from crowd sourcing.