This is why Groupon isn't worth much though. There are no legal, ethical, or technical reasons for not contacting everyone who uses them and offering them a bet

This is why Groupon isn't worth much though. There are no legal, ethical, or technical reasons for not contacting everyone who uses them and offering them a better deal. The beautiful thing about e-coupons is that they don't cost anything to issue so there's pretty much no risk to the merchant for trying another company. The only lock-in possible in this industry is customer satisfaction through value, which Groupon is notoriously bad at.