A raked hand is one hand played at a cash table.
Many industry leading websites have the similar feature/promotions where you have to complete some missions (play x amount of hands, get x pair, etc.) in order to unlock some reward. Usually these rewards are close to nothing (few cents).
@TonPoker can you post your detailed rake structure here across all formats? It would be helpful if you can post all leader boards + cashback rearwards also, I just want to check if if is possible to beat the rake in your platform.
Very well, gambling bonuses is like compensation for completing a certain task while gambling, some will go higher as you keep you rollers on that is why those big rollers get the highest bonuses from casinos and the bonuses come from with the games their play.
Rake back is calculated based on your total previous wager, if you have records of your weekly or monthly wagering amount you can even calculate some of those bonuses.