Then I stumbled across this great post from Jenny at Southern Savers about this very issue - here is the link. Jenny has spoken with the creators of the e-coupon sites and she brings up a lot of great points and answers several frequently asked questions.
This post is not to determine right and wrong, it is simply to provide you with more information on the subject. An educated couponer is the best kind of shopper - you always want to make sure you have as much information as possible. What you do when couponing is completely up to you, but you have to be comfortable with your decisions. Hopefully, this link will help shed some light on the history of e-coupons so you can make a better informed decision. What are your thoughts on stacking these two types of coupons?