Boilermaker,
I have also heard that the reason they can do that is because they do not have to worry about certain costs
I don't know about fuel I wouldn't be surprised if its free, but virtually everything in DOH is owned by them (e.g. Ground Handling, Catering etc...). They also have a very low cost structure compared to other airlines in the Gulf for several reasons. So the money saved helps compensate for the low yeilds.
Anyway all there losses are covered by the government so they can afford to lose money. The government will basically give QR all they need untill they can get on their feet and have the IPO before then end of this decade.