My opinion is that you make your own independent exchange. Even if the fees on the exchange might be so low that they only pay off its expenses, you will profit more simply because of the reduced spreads on bitcoinica (more people, like me, will use bitcoinica more often - I love bitcoinica but sometimes the spreads are just too high... simply because Gox has to have a piece of the cake)
You are the only one running an exchange type service who has excellent communication with their customers. Compare to gox which wont even reply to emails, will constantly "forget" tickets, will do crazy stuff like demand an ID and freeze up your money for no reason etc.
Actually, with 0.1% fees, you should profit off of that too, simply because you will take pretty much ALL the volume off of other exchanges (unless they tighten up their game that is, which doesnt seem likely). Traders will also most likely trade more. Spreads will decrease because traders will be able to profit off of smaller difference (e.g. buying and selling at a 0.4% difference would be profitable, compared to 1% needed in mtgox)
Ok I'll bite.
Have you considered how difficult it would be for you to offer payment services?
Why would you enter the thread just to say something negative? As an adult, dont you find it inappropriate to just enter the thread to dispraise a 17 year old in his business venture... As a matter of fact, it seems like mr.Tong is the adult (for not calling you an asshole, which you clearly are) and you are the "kid".
Is it perhaps jealousy? You have to realize that, since he offers better service than any other exchange, and is about to offer an exchange service for 1/6 the price of the top exchange, with same volume... The fact that he will offer BitInstant transfers (smart move there mr.Tong) means everyone from gox will most likely go to his exchange, unless of course they like being goxed.
Thank you mr.Tong for your service, and thank you for taking into consideration what the community might think of you opening up an exchange. To date, I have not seen a single exchange which can talk the talk (service) AND walk the walk (offer volume).