This is my first time hearing about it. I am curious to exactly how it works. From just looking at their website, it looks like you earn 1% to start but can earn up to 10% by inviting friends.
I am willing to give it a shot to see how it works. I don't mind trying new things! 
This is similar to cashback sites like Ebates or BeFrugal. BeFrugal offers up to 10% cashback but that is only in the "Amazon Exclusive Apparel" category. All other categories have varied percentages of cashback and some categories have 0 cashback.