I think coupons are a good thing for online stores, but you don't want to over-do it. For example, there is a printing company that I buy business cards and stickers from, and they are so aggressive with the coupons that I don't place an order without one, because I know every few days they'll email a new code. That's fine, but it's a bit tacky (not that it keeps me from shopping there). In the long run I think it's better just to offer good prices up front, and then the occasional coupon for a special occasion like Black Friday.