That's one million consumer accounts with no FDIC insurance, no surety bonds, and no other backstop in the event of a problem. I'd love to see a Coinbase blog post about why Coinbase doesn't need to be licensed like every other MSB registered with FinCEN.
"1.1 Coinbase helps you make payments to and accept payments from third parties. Coinbase also provides a bitcoin wallet service where you can store your bitcoin. Coinbase also allows users to buy and sell bitcoin. Coinbase is an independent contractor for all purposes. Coinbase does not have control of, or liability for, the products or services that are paid for with Coinbase services. We do not guarantee the identity of any user or other party or ensure that a buyer will complete a transaction. Coinbase is not a money transmitter. Coinbase assists its users in Bitcoin transactions."
https://coinbase.com/legal/user_agreement
You hook up a bank account, "transmit" funds from a bank, receive virtual currency (and in reverse) but they are an independent contractor, assisting with the process. Very interesting approach.
A simple person might say the service very much looks like a money transmission, money exchanging business. The fees for acting as a money transmitter without licenses is supposedly up to $1k/incident.