A few issues: 1. Groupon deals aren't only valid for one day, thus the restaurant owner has no idea when people are going to be in the restaurant or not. 2. I

A few issues: 1. Groupon deals aren't only valid for one day, thus the restaurant owner has no idea when people are going to be in the restaurant or not. 2. I reject the notion that I restaurant owner would prefer to serve a full restaurant at half price over a half full restaurant at full price. From my discussions with businesses who use Groupon, they mostly see it as a tool to drive repeat customers not one-time customer volume. Very few restaurants can make ANY money at 50% menu price, much less at 25% menu price (after Groupon takes their cut). 3. I would be willing to bet the 'tipping point' effect of Groupon on the sharing of deals is nearly insignificant. I think a far larger driver of sharing these deals are deals that require multiple individuals to participate. (e.g. I bought a coupon with 15 of my friends to go paintballing in a few weeks)