Folks, as our buddy cepheid can attest, there is a reason why it is so difficult to earn miles or cash rebates for Amazon purchases. It is because Amazon's contract with its "affiliates" (those who earn click-through commissions from Amazon) are expressly forbidden from splitting those commissions with others (e.g., the end users of their websites).

So, for example, shop4miles is apparently violating its contract with Amazon, and several posters here have "outed" that fact publicly.