I don't know about AirBnB. People have been renting rooms for as long as they've been traveling, and vacation rentals existed long before AirBnB existed -- but they certainly make things more efficient than the way they used to be. That said, if I'm counting "washing machines", then perhaps AirBnB should count, too (or anything that increases efficiency of a thing we already do by an order of magnitude; it's an interesting debate, and I'm not sure which side I'm on).

I agree with you on AdWords, though. That was really the first time advertising was made quantifiable on a large scale (the innovation), and it resulted in a new industry.