I will throw out some questions to get things going:
1) How did opentable overcome the Chicken and the egg problem? Did they build up a roster of restaurants before they even opened the consumer side of things?
2) Did OT start with just San Francisco? How fast did they expand into other cities? Or did they go from SF to nation wide in two steps?
3) How hard was it for Opentable to change the way people made reservations? Was the market ready for it or did it take a long time to get people to make reservations this way?