What I find most interesting about Coinbase is that they quote your selling exchange rate the moment you place a sell order. If I click "sell" right now, they lock in the $13,000 exchange rate or whatever it is. The amount that shows up in my bank days later is exactly what they quoted at the time I placed the sell order. When people start selling off, this policy is either going to drive them to bankruptcy or create a lot of unhappy customers.