I just found this and hope JM finds it useful...

I have two citibank credit cards and when I logged into my accounts, it showed the link to there cash bonus account. The way it works is that if you use their cards to buy instore/online from their network merchants, you will get an EXTRA cash bonus on tops of the dividend you will get on the cards. They have large network with all the general stores there. And all you need to do is activate your card for this extra benefits.

Hope JM who already have Citi cards do not miss this perks, I did not know it until today...