We note with interest the new partnership between New York Magazine and Foursquare, the location-based service now in 21 cities that lets friends see where you have “checked in” and lets you vie to be mayor (hail Outside.in’s Camilla Cho, our mayor at the recent BIA/Kelsey Marketplaces conference).

New York’s 7,000 followers on Foursquare will have access to tips from the magazine’s online database that includes 5,000 restaurants, 1,600 bars and 5,500 stores. True to form, most of the initial items are food and bar oriented, but there are also cultural, retail and sports items.

The addition of New York, which has both local and national readers, complements other sites that have joined up with Foursquare. The only other “local” site is Time Out New York, but local/vertical interest is also captured by partners such as Zagat, and to a lesser extent by sites such as Bravo, Askmen.com, The History Channel, Bon Appetit and Gossip Girl.

Aside from the partner deals, Foursquare has been rapidly developing in other directions. For instance, it has localized national deals with chains such as California Pizza Kitchen, ChiChi’s and Athletic Warehouse.

It also has local deals, even in cities where it has not formally launched, such as San Diego. One local deal that caught my eye was for Del Mar Racetrack, where the mayor will be entitled to a VIP paddock tour, four clubhouse admissions and his or her name on the tote board, and will watch a race from the Winner’s Circle.