This game is nearly everyday on the front-page of reddit/digg/etc... , and a lot of people are making youtube videos of their creations. With all this web coverage he doesn't need to spend money in advertising :).

A game that makes people build something (even if useless, it's still a game) and make it easy to share, instead of bovinely click around like in Zynga's games. Recipe for success?

Prepurchases? Pretty sure that could be the problem - - PayPal doesn't permit charging someone for goods that aren't going to ship immediately.

Yeah, it blew up on Reddit a couple of weeks ago. For some reason the story didn't take hold over here on HN. This is why I read both sites - often you get great stuff over there that doesn't make it over the front page karma barrier here because not enough people read /new ;-)