This is the same question I was going to ask, as a bitcoin newbie. It seems crazy to me that mtgox is both the exchange as well as the brokerage. Actually it seems crazy that there is almost no information about mtgox whatever, yet it appears to control millions of USD worth of bitcoins.
Basically, if people expect a fully functioning bitcoin exchange, they will need to duplicate some or all of the existing market microstructure we see in other exchanges around the world.
If people expect a burgeoning and robust bitcoin economy, there must the be an financial ecosystem that inspire confidence in people.