Well, it's sort of two years old, and you've been able to support yourselves by pre-orders, and bunches and bunches of people play it and have been playing it for a while. It's not VERY old, but it's had a strange thing happen to it - it became a classic even though it hasn't had a "release" yet ^^
And there's long lets play series of people playing its alpha and beta builds
It's kind of like there being a Dota 2 without there being a Dota 1