As the internet economy heats up again to the approximate temperature of the surface of the sun, quite a few aspiring publishers and newer content sites have asked me about how to target their advertising geographically.
Geotargeting is one of the most commonly used targeting options, so regardless of whether you're an ad seller or an ad buyer, you should be familiar with geotargeting and how it works. There are a variety of methods used to determine the location of a web page viewer, and not all methods are created equal. If you're a seller, you want to offer the most accurate targeting possible to your advertising clients. If you're a buyer, you want to ensure that the targeted ads you buy are consistent with your client's expectations for spill (ads served into markets other than the ones you're targeting).