I'll just say that it's a very simple skill-based, text-based multiplayer race-against-others game (something like a multiplayer speed Scrabble). It has almost no graphics and uses AJAX.
how is it not earning a livable wage with 2 million users?
It's livable if you have very low expenses, but in my limited experience, 2 million users just aren't enough for a free website to make good money. Maybe I'm hugely under-monetizing the site somehow, but I don't really see a good source of revenue other than from ads.