I started hitting them pretty aggressively starting last December, and so far I'm just over $14k for the year between me and my wife. Great way to make some extra cash with very little effort. Really nice that I can change my direct deposit account at work myself without having to bug anybody.
Just wanted to pass that along for anyone looking for an easy way to make some extra money. I estimate I've probably spent 15 or so hours over the past year on this.