This is a tough question. To be completely honest, none of them are amazing. Opentable does a good job of telling us which guests are first-time diners, but I still have no way of knowing if they would have come in whether OT existed or not.

The biggest problem that a lot of restaurants face is that we simply don't know which marketing tactics are working. The only thing we see is if total revenue goes up or down. This causes us to just throw everything at the wall and guess what sticks based on revenue changes.

To some extent coupons work because we can simply track how many are redeemed, but like I mentioned in my original post, this cheapens the product often and causes the guest to perceive that the food is worth less than the normal price.

With that said, there is no homerun (at least that I know of) customer acquisition method as of right now.