Gap clothes have never fit me particularly well so I’d normally ignore a 25% off sale, but the novelty of the Foursquare tie-in caught my attention.

Eventually the novelty of Foursquare will wear off; some say it already has. I don’t know about you, but I’ve had very few of the serendipitous “hey my friend just checked in at a bar around the corner; let’s go!” experiences that were the initial selling point to consumers. I rarely remember to check in these days, and collecting badges, mayorships, and points lost their thrill long ago.

But I don’t think this matters to Foursquare’s long-term success. The game was just a Trojan horse - a way for the service to collect a critical mass of users. It doesn’t matter that people grow tired of the game mechanics and stop checking in to bars after a couple months. That’s not the point.

Foursquare’s actual goal is to be the Google Analytics of the real world. By tying promotions to check-ins, businesses can easily track the effectiveness of their marketing campaigns. This is worth a LOT of money. Rather than flying blind or making guesses based on sales numbers after the fact, brick-and-mortar businesses can hone their marketing the same way that web businesses do. Eventually someone will close the loop by tying Foursquare check-ins to actual purchases, and business will be able to do real-world conversion tracking. CPC (Cost-per-conversion) revolutionized advertising on the web; imagine the impact when that model can be used everywhere else.

I’m hardly the first person to think this, but it’s only recently that Foursquare has demonstrated that they’re really moving in this direction. Should be interesting to see how Facebook’s inevitable location product alters this market.