25% off at Gap with Foursquare

A new Foursquare promotion happened at the weekend in the US.  People checking in at Gap got 25% off their bill.

I'd love to see the stats, and I'd love to know what Gap are doing with the data they're getting from it (level of spend, discounts per store, most popular stores, most popular things bought etc).  In fact it was so successful (apparently) that they've now extended it until 22nd August.

This is an interesting example of Foursquare being used like an emailed voucher, and it shows one example of the potential of the service (and of location-based apps for retailers).

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