In 2010 I received $197.42 in cash back ($10 came from referrals) from Ebates. In total, I have received $325.75 since I joined in 2009.
I love getting cash back from my purchases. I even saved about $50 on our trip to San Francisco this past summer by booking it through Ebates.
The downside, I spend A LOT of money shopping online, as evidenced by the amount that I got back.