The Associated Press had a nice article yesterday (reprinted here on the CNN website) about how web-based geolocation technology can figure out where you are from your IP address–at least, most of the time.

Type “dentist” into Google from New York, and you’ll get ads for dentists in the city. Try watching a Cubs baseball game from a computer in Chicago, and you’ll be stymied. Pre-existing local TV rights block the webcast.

The same technology is also being used by a British casino to keep out the Dutch and by online movie distributors to limit viewing to where it’s permitted by license, namely the United States.

Privacy advocates seem most upset that the technology will be used to mislead web visitors with different prices or specially-edited content.

Personally, I’m concerned that the widespread use of geolocation technology will fundamentally change our idea of what the web really means. I’m concerned that errors in the geolocation technology will unfairly penalize people. And I think that there should be a way to turn it off without penalizing the user.