Location-based marketing onto mobile devices has been touted for years at this point, repeatedly claimed to be the "next big thing" and "about to go hot".
So, what's kept it from doing so already?
Frankly, balance, control and value are all aspects which decide whether a consumer wants this sort of stuff. I might want occasional coupons or discounts, but not every 15 minutes. I might want to hear about shoe sales nearby, but not auto repair discounts. And, even if it's the content and frequency that I want, I still might not be thrilled if the discount value is only marginal.
It's clear that user opt-in and controls need to somehow be included for this stuff to really work -- otherwise, we all get irritated and tune it out.
So far, no one's really found a balance or a method that fine-tunes for individuals' needs, IMHO.