AT&T has introduced a new location-based "ShopAlerts" with Placecast in four US cities: NY, SF, Chicago and LA. This is opt-in "push" marketing via SMS or MMS tied to "geo-fences", and send text alerts about new products, special offers, and events from your favorite brands when you are nearby stores. It all comes included with America's best wireless service.
Once a user has opted-in, Facebook or many other places (e.g., display ads online) that person will receive alerts (offers, promotions) when he or she physically enters the designated local area, which's defined by the advertiser (e.g., a mile from retail store XYZ).
Initial advertisers signed on include: HP, Kmart, JetBlue, SC Johnson, Kibbles 'n Bits, Nature's Recipe and the National Milk Mustache "got milk?" Campaign. This program will work for marketers trying to drive in-store traffic or simply trying to reach mobile users in particular markets.