Quick question though, what is the main difference between Bitstamp and Coinbase? How come Bitstamp allows buy/sell limits but Coinbase doesn't? Is there a reason Coinbase has a limit to how many BTC you can buy? Does Coinbase also allow business to use bitcoins like BTC-e?
Coinbase is not a full-fledged exchange like Bitstamp; I assume because of the legal-ramifications in the US of doing so. I'd watch for Coinbase to announce a full exchange, though... This round of funding is probably large enough for them to get money-transmission licenses in most states, thereby paving the way for them to operate a full exchange in addition to their existing services.