Location-based shopping services (LBS) have made many headlines recently, and studies have shown that users actually like receiving ads and offers well-targeted to their interests. Couple that with an influx of Tier 1 venture capital and the show-stopping Facebook Places, with which several startups have already joined forces, and it’s no wonder LBS is suddenly such a hot topic in the mobile sector. That doesn’t necessarily mean LBS shopping apps will be easy to implement. A number of challenges — privacy concerns, scaling issues and check-in integrity among them — provide a potential barrier to widespread adoption. This note examines both the drivers and inhibitors for making location-based shopping services a mainstream phenomenon, and includes focused profiles of Facebook, Twitter, Google, Loopt, Foursquare, BrightKite, Whrrl, Gowalla, Plancast, Groupon, AisleBuyer, Bizness Apps, Offeretti, ShopAlerts, Shopkick, Bakodo, Stickybits, Yelp!, Geodelic Sherpa, WHERE, MyTown, InCrowd, SCVNGR, Waze and Layar.