Cake poker have just implemented a new rewards scheme called gold stacks. It's basically just a small additional award that is allocated based on how many gold chips you collect. (Gold chips being an existing awards scheme).
At first the rewards are just gold chips, but after that they become pending bonuses that you then clear like a reload bonus, and as you get even higher they become purely cash bonuses.
Some guy on 2p2 worked out that the impact is about a 2.5% to 10% increase in effective rakeback depending on how many levels (ie stacks) you've already completed.
I'm not sure if i'll get too far through it, but hey, its some more free money so I won't complain. (although if they stop doing reload bonuses I will be very disappointed).
Fulltilt bonus cleared: $230
Fulltilt bonus remaining: $70
Days left: 11
Current bankroll: $22,800
December time played: 10h
December profit / (loss): $450