What's the easiest way to do some (light) geotargeting on a site? I'm looking to buy some traffic to a site that is using YPN who's not too crazy about non-US traffic. The source of the traffic I am looking to buy does not discriminate visitors by their location in the world but I want to show non-US visitors different ads so I don't get banned by YPN. Does that sound like a valid concern, by the way? Anyways, how would you do just this much geotargeting (US vs. non-US traffic only)? Thanks!