You must be able to, as I do not get ANY daily emails. I joined in 2011 when buying my Nook (wow that sounds dated), because they were offering a cash back bonus of $25 gift card with your first purchase through them over a certain dollar amount. Since then I have amassed $200 back. Not as impressive as a PP who got $77 in one check, but the bulk of my shopping is clothes, shoes, etc. I have the plugin on chrome (along with honey and retailmenot for coupon codes). So when I'm on a retail website a little box will pop up on the right hand corner at the top, maybe 2 inch by 1 inch asking if I want to activate their cash back offer.
I always activate it if it's there, but if I can get a better price elsewhere on the same item but without cash back, I will usually go with the better price. Some of the best cash backs I have gotten though are on photo services like snapfish.