A California federal district court has dismissed a case for lack of personal jurisdiction because the plaintiff did not sufficiently prove that the unknown user of a specific IP address was located in California. Celestial Inc. v. Swarm Sharing Hash, 2012 U.S. Dist. LEXIS 61559 (C.D. Cal. 2012).
The plaintiff, a producer of adult pornography, had filed suit against multiple John Doe defendants who had used peer-to-peer networking software to download copyrighted videos. To satisfy personal jurisdiction, the plaintiffs asserted that research had "placed the IP addresses of the Doe Defendants in California." According to the plaintiff:
Determining the nation of an Internet user based on his or her IP address is relatively simple and accurate (95%-99% percent) because a country name is required information when an IP range is allocated and IP registrars supply that information for free.
Determining the physical location down to a city or ZIP code, however, is more difficult and less accurate because there is no official source for the information, users sometimes share IP addresses and Internet service providers often base IP addresses in a city where the company is basing operations.
Accuracy rates on deriving a city from an IP address fluctuate between 50 and 80 percent, according to DNS Stuff, a Massachusetts-based DNS and networking tools firm.
Even when not accurate, though, geolocation can place users in a bordering or nearby city, which may be good enough for the entity seeking the information. This happens because a common method for geolocating a device is referencing its IP address against similar IP addresses with already known locations.