Gap have extended their BlackMagic social media campaign exclusively for Foursquare users until August 22nd, extending last week’s one day Facebook-Twitter-Foursquare event promoting the launch of their new women’s black pants; 25% of all in-store purchases with a Facebook coupon (printed), Twitter code (spoken), or a Foursquare check-in (shown).

If checking-in on the geosocial network seems arduous, just give the cashier the register code BMAGIC25.

Gap is the latest retail brand to use Foursquare as a social commerce tool to drive traffic footfall and build loyalty in retail stores by rewarding people for checking-in to stores, and in so doing share store promotions across their social graphs.

With Facebook and Twitter launching geosocial features, dedicated loyalty apps like ShopKick, (used by Best Buy and Macy’s) WeReward and TopGuest often doing auto-check-ins, and Forrester advising marketers that it’s too early to jump on the geosocial marketing train anyway, the Foursquare minnow and its smaller siblings (Gowalla, Brightkite et al) are caught somewhere between a rock and a hard place.

Nevertheless, a number of brands are – or have been running Foursquare promotions – or “Specials” as Foursquare calls them.  Here’s a round up…

• 1. American Eagle Outfitters: Check-in to unlock a 15% discount
• 2. Ann Taylor: 25% off for mayors, check-in 5 times to unlock a 15% discount
• 3. Ben & Jerry’s: Free fourth scoop for mayors, check-in to get 3 scoops for $3
• 4. Coach: Free cologne for first 200 check-ins at new NY store
• 5. Chili’s: Free chips and salsa for check-ins
• 6. Crunch Fitness: Check-in for a free 7 day pass
• 7. Diesel: Free t-shirt for check-in (one day only)
• 8. Domino’s (UK): Free pizza every week for mayors, free side for check-ins
• 9. Gap: Check-in to unlock 25% discount
• 10. Golden Corral: Mayors eat free, one in five check-ins eat free, all check-ins entered into iPad sweepstake
• 11. Jimmy Choos (London, UK): Catch a checked-in “CatchaChoo” representative snapping Twitter photos of Jimmy Choos and get the shoes (Jimmy Choos Treasure Hunt)
• 12. Juicy Couture: Mayors get 30% VIP discount
• 13. Ligne Roset: 25% off for check-in (Togo collection)
• 14. North Shore Bank: $5 Subway giftcard for mayors
• 15. Pepsi: Check-in to Pepsi-pour locations, buy Pepsi and get Pepsi Loot reward points for free downloads
• 16. Pizza Hut: Free bread sticks for mayors
• 17. Radioshack: Mayors get 20% off, check-ins get 10% off
• 18. Sephora: First to check-in with Real Housewife badge to Sephora’s weekly “Secret Store” (revealed on Twitter) gets $100 voucher
• 19. Sports Authority: Mayors get  $10 instant Cash Card
• 20. Starbucks: $1 off Frappucino for mayors
• 21. Steve Madden: Check-in to receive a 20% discount $50+ purchases
• 22. Tasti D-Lite: Checkin to earn additional loyalty program reward points
• 23. Wagamama: Free juice for mayors, free miso soup for every fifth check-in
• 24. Wholefoods: Every fifth checkin get free scoop of gelato in store café

Scanning through these Foursquare promotions, it’s clear that Foursquare is being used primarily as a loyalty rewards platform/couponing channel offering four types of rewards or “Specials” for customers

• “Check-in Specials” – unlocked when a user checks in to a venue a certain number of times (“Foursquare says you’ve been here 10 times? That’s a free drink for you!”)
• “Mayor Specials” – unlocked only by the Mayor (the user who has checked in the most in last 60 days)(“Foursquare has deemed you the Mayor? Enjoy a free order of french fries!”)
• “Frequency-based Specials” – unlocked every X check-ins (“Foursquare users get 20% off any entree every 5th check-in!”)
• “Wildcard Specials” - unlocked with special conditions (“Show us your foursquare X badge and get a free drink!”)

Few retailers have published the results of their Foursquare campaigns – although pizza chain Domino’s attributed a 29% UK sales increase at least partly to its social media marketing campaigns.  Nevertheless, Forrester argue that adoption of geosocial apps is still too low to warrant marketing investment.

Sure, we not in Minority Report yet, but given that it’s free to run promotions on Foursquare, we’d recommend that brands and their agencies use Foursquare as an experimental sandbox for geosocial marketing.  The time for goesocial marketing will come, and when it does, it’ll be those with “the knowledge” who’ll profit.