Has anyone heard of or used the new-ish app, Foursquare?  It’s one of the zillion new “startups” coming out of New York.  It works like this; you arrive at a restaurant or bar or a party, and you “check in” on Foursquare rather than sending a mass text to a bunch of friends telling them where you are.  Then, instead of responding to and receiving a bunch of mass texts from friends telling YOU where THEY are, you peruse Foursquare to see where everyone is.  A recent New Yorker article commented, “Foursquare is also useful if you want to let everyone know that you are.”  In short, it’s a new kind of “ambient awareness,” the phenomenon we talked about in our conversations about Twitter.  At the same point, the new app to have a slightly more complex function as it does more than just tell the world where you are at a given moment–it’s a time-saver, it’s convenient, and, as the New Yorker put it, “Foursquare is essentially an urban network of hipsters, their favorite haunts, their favorite food and drinks—a marketer’s dream, in other words.”  Aside from letting your friends know where you are, you’re also giving marketers access to your social patterns, which is extremely useful information that can and likely will improve advertising strategies by providing agencies with easy and instant access to market research.