Please help me understand where freebitco takes a lot of funds(hundreds of bitcoins) to pay its users every day since there aren't banners on pages 
Dice game income, mining income... There are many people who uses the site depositing money to play Dice game and most of these people lose their money playing like at any other casino. I think this is the main income from FreeBitco.in, but only Myfe or wetsuit can confirm it exactly.
