>6. Their measurement method is very inaccurate. Asking people where they found out about you has been proven to be very very inaccurate. Instead, give them a coupon and track based on that.

I've found more often than not people simply take advantage of the offer of the coupon, and rather than "new fans" of your franchise, you simply get one-timers. They're bargain shoppers, not potential repeat customers. This is the same problem that plagued many Groupon clients. So while it might offer you a hard and fast showing of how many people are willing to try your place with a coupon, it doesn't prove a) your ad has reach on its own merit, or b) that you're targeting the right group with your ad.