IP address pinpoints location

Dear PropellerHeads: I'm no privacy nut, but I get a little uneasy when Web ads invite me to "Click here to find singles in Richmond, Va." How do they know where I am?

A: I'd be more concerned about how they knew you were single! Maybe they took control of your webcam and figured anyone who combs his hair like that must live alone? OK, calm down: the Internet is still the place where "nobody knows you're a dog," as they used to say.

For now your marital status is somewhat safe, but it's open season on your whereabouts. On the Internet right now it's all about location, location, location.

Your ad probably used "IP geolocation" to determine where you were. Internet connections are assigned "Internet Protocol" addresses, which are sets of numbers separated by periods, like "99.18.50.219" (see whatismyip.com for yours).

Internet providers allocate ranges of IP addresses to different localities. Companies like MaxMind (maxmind.com) sell databases of IP-to-location mappings. Punch your IP into http://bit.ly/cFXn2rto see where they think you are.

IP geolocation is only accurate to the city and is wrong about your state 15 percent of the time, according to locationaware.org. Good enough for cyber-personals, but insufficient for turn-by-turn directions, "hyper-local advertising," and alerting you when your buddies are nearby.

These are some of the uses envisioned by the World Wide Web Consortium (w3c.org), which added geolocation capabilities to HTML5, the upcoming version of the computer language used in Web pages. The Big Five browsers - Internet Explorer, Firefox, Opera, Google Chrome and Apple's Safari - announced support in upcoming products, while Loki (loki.com) plugs into existing browsers to "location-enable" them.

How do they find you more accurately than IP geolocation? Some phones use their built-in GPS chips. Others phones and some computers gather information about nearby cell towers and Wi-Fi networks.

Skyhook Wireless (skyhookwireless.com) operates a service used by the iPhone, the latest Macs and some Dell netbooks. The phone or computer sends the MAC addresses (unique IDs) of nearby wireless routers to Skyhook, which maintains a database of router locations. They've paid people to drive around the country with special equipment that records location and data about nearby routers. They can combine this with information from GPS and cell tower signals to pinpoint devices within 10-20 yards.

Microsoft and Yahoo use Navizon (navizon.com) for their location-based services. Navizon relies on "crowd-sourcing," offering cash to people who download their products and submit location data back to them to build a "collaborative database."

These "hybrid positioning systems" are more accurate than IP geolocation, but don't cover rural areas as well. They also work better for laptops, since many desktop computers don't have wireless connections.

A lower-tech approach used by some sites currently is just to ask users where they are in order to provide more targeted services.

So privacy nuts are going to find it increasingly difficult to carry mobile phones or work on laptops without being found, because when it comes to The Next Big Thing on the Internet, location is "where it's at." Now, about that comb-over...

When the PropellerHeads at Data Directions aren't busy with their IT projects, they love to answer questions on business or consumer technology. E-mail them to questions@askthepropellerheads.com or contact us at Data Directions Inc., 8510 Bell Creek Road, Mechanicsville, VA 23116. Visit our Web site at www.askthepropellerheads.com.