The site costs dramatically less than you probably think. We're thinking of upgrading soon to more powerful hardware, but even that upgraded hardware is dramatically cheaper than you think. There are two ways to do things, you can either spend lots of money on server hardware and then keep throwing money at it to make it faster, or you can run a custom environment, tune it for performance, and keep everything light and efficient. Doing the later can give performance gains in the 10X to 50X range over a conventional setup.
You really wouldn't believe me if I told you how little we pay.
