Did this paper provide an early proof for the Groupon model?

Conitzer and Sandholm introduced the idea of using auctions to allow individuals to offer to match the contribution of others. We explore this idea in a social network setting, where individuals care about the contribution of their neighbors, and are allowed to specify contributions that are conditional on the contribution of their neighbors.

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We show that if the social network is strongly connected, the mechanism always has an equilibrium that raises the maximum total contribution.