With regards to why we don't arbitrage, I answered this in another HN comment: http://news.ycombinator.com/item?id=823327 http://news.ycombinator.com/item?id=82

With regards to why we don't arbitrage, I answered this in another HN comment: http://news.ycombinator.com/item?id=823327 http://news.ycombinator.com/item?id=823327. There are a number of reasons, but one of the biggest is transaction costs. With regards to the TAM, I totally agree that we dropped the ball when we were on stage. I guess the pressure of being under the bright lights got to us. But we do indeed know our TAM; if you happen to be interested I can send you an Excel model that calculates it.