Subscribers who opt into the free service, by texting a shortcode, will receive SMS offers when they near participating stores, using geo-location technology.
They can also customise their preferences online in order to receive more relevant offers - which seems like an unnecessarily removed step, especially given the site isn't mobile-optimised. It's the kind of thing which could easily be dealt with in an app, but given that AT&T has opted to use SMS, it seems that the operator is trying to sidestep any fragmentation issues which might hinder adoption.
The service appears to be an evolution of AT&T's Placecast-powered ShopAlerts service, which launched last year in a small selection of pilot cities.
Retailers and brands signed up to the Alerts scheme currently include Gap, Staples, Duracell, Motorola, and Discover.