From the Web site of the Turn ad agency
In a move that should surprise no one, Foursquare will be working with one of Facebook's ad partners to direct location-based ads to its users beyond their check-ins.
The deal was reported by Ad Age, which cited “unnamed executives familiar with the matter,” although both Foursquare and Turn have declined to comment. The ad partner is Turn, and the partnership will allow the agency to identify Foursquare users and then target display and video ads to those users as they travel the Web. Turn specializes in using data about online behaviors so that its clients can, as it says on its website, "retarget customers you know were already interested."
With Foursquare in the mix, targeted ads will be triggered by check-ins in addition to cookies, but check-ins will also be cross-referenced with cookies to better establish user profiles for post-Foursquare ad targeting.
In April, there were reports online of a leaked presentation purported to be from Foursquare that showed the company’s projected strategy for using its data for ads.
The presentation indicated that Foursquare has been planning to link user check-in data at a physical place with a DSP partner, which would allow an advertiser to find what the presentation described as "Foursquare users outside of the Foursquare app experience."
Foursquare’s treasure trove of data is derived not only from the check-in's made by users through its app, but also from location data received from other apps that have integrated Foursquare, such as Evernote.