Barry Diller runs his company, IAC, like a used-car dealership. That comparison is meant to disparage neither Diller nor used-car lots but to capture the shark-toothed, high-velocity, unsentimental manner in which Diller conducts business. How many photos of Diller have him wearing the fake grin of the car salesman, the one that says “I’m your friend until the deal is done or abandoned, and then you’re just another future mark to me”?