You must have CSGOEmpire.com in your Steam Profile Name to be eligible for the bonus pot.
1% of total bets will go into a bonus pot. In each round, there is a small chance (that round's total bet value / 1000000) of the roulette wheel landing on a special green "Bonus Pot" icon, pictured above. When that happens, the bonus pot will be split proportionally between all eligible players in that round.
The amount you earn from the bonus pot depends on your bet amount that round. For example, if the bonus pot hits and the total bet value that round is 500 coins and your bet value that round is 250, you will earn 50% of the bonus pot.