I’ve written several times about earning miles for almost all online purchases that you’re going to make anyway (such as here and here).

One of the challenges is keeping up with all of the partnerships — which sites allow you to earn miles, and through which programs? Do you actually have to check all the different mileage malls each time you want to buy something, and ever worse compare the earning rates as well?

Andrew Cram a chart that compares the earning ability of several hundred commercial websites across nine different mileage programs. A truly handy reference.