[throwaway283719]

Yes, the exchange fees are astronomical.

It looks like the spread if you wanted to trade 10BTC is around $2 (just looking at the last hour or so of data).

On BitStamp the exchange fee is 0.2% (at minimum - can be higher) so trading 10BTC twice (one buy, one sell) would cost you $20 in bid-offer spead, but about $26 in exchange fees - insanely high!

Usually you expect the exchange fees to be 1/10th to 1/5th of the spread. With fees this high and no rebates, I wouldn't even be sure I could make a profit as a market maker even if you could exit every position immediately.