Netflix is very very strict on who does and does not get miles. I had trouble as well. Apparently they have been known to go as far to deny people who have never signed up but the previous home owners use to have an account. So if you've ever had someone in the household that has had an account or you had one years ago you will not earn anything.

Delta use to have a deal where you could get 5,000 sky miles. If you have an amex delta card the min. value is 1cent per mile. I always get at least 2 cents or more on my miles...