What is this exactly? There's no explanation on the site of what it is or how it works.
It's a ponzi game. The site was obviously made by backend software engineers - as it works great but the design leave a lot to be desired.
If you go to http://bitcoinduit.com
, the site front page, there is a link to the rules.
They are deliberately vague. I think their stance is if you don't know how it works, then don't play. Ponzi games like this have been running in the gambling section for a while, so most of us die hard gamblers already know how they work. The important part is that it's completely transparent. All parts of the game are revealed. How much is in the pot, how many people are in line in front of you, etc. So you can make an informed decision on betting.
Anyway, if you bet smart, there is a lot of BTC to be won. See my sig.