  In this paper, we design gross product maximization mechanisms which
incentivize users to upload high-quality contents on user-generated-content
(UGC) websites. We show that, the proportional division mechanism, which is
widely used in practice, can perform arbitrarily bad in the worst case. The
problem can be formulated using a linear program with bounded and increasing
variables. We then present an $O(n\log n)$ algorithm to find the optimal
mechanism, where n is the number of players.
