Very convenient service. Just works! Curious about business model. I'm sure that services like rapidshare could be profitable (bad interface, worsen service fo

Very convenient service. Just works! Curious about business model. I'm sure that services like rapidshare could be profitable (bad interface, worsen service for free users etc), but it not so clear how to get profitable such service with so strait forward interface. Other file-sharing service with simple interface that I've tried to use was filesavr.com but after some time it became very unstable.