Google's chief economist, Hal Varian, says that the way to get rich is to own an expensive good that's complimentary to a free good (if you have a monopoly on r

Google's chief economist, Hal Varian, says that the way to get rich is to own an expensive good that's complimentary to a free good (if you have a monopoly on right shoes, and left shoes cost nothing you're going to do pretty well). My guess is that Twitter is engineering the supply by making tiny messages to all of your friends ubiquitous. I don't know what expensive analogue they'll create -- perhaps analytics, perhaps ads or product placement -- but it's pretty hard to end up with nothing when you have a huge customer base and you keep expenses low. In financial terms, that's a low-cost option on whatever business model might eventually show up to take advantage of the situation.