On Dec 20, 2007 8:13 PM, Greg Skinner <gds@best.com> wrote:
Personally, I have trouble accepting some of the claims the geotargeting companies have made, such as Quova's 99.9% to the country level, and 95% to the US state level. ( More info at http://www.quova.com/page.php?id=132 ) Perhaps I'm just part of the
The trouble with a claim of "95%" accuracy is the method of determining the accuracy of the measurement has not been indicated, and there are _many_ IPs out there. With no method of obtaining the statistic indicated: there is no evidence I saw that 99%/95%, weren't possibly just made up numbers for the purpose of aggressively marketing a product. I agree it is not very believable that a geolocation service properly locates 95% of all ip addresses to within a state/city. Due to the existence of various types of proxies and anonymizer services, visible IP often does not reveal original requestor details. RIR records give contact information for an organization utilizing IP space, that's not the same as the physical location of nodes -- it makes the RIR data an unreliable source of information for that usage. This information is not necessarily always up to date in the first place. Nodes on the very same RIR allocation may be geographically distant. No more reliable than performing traceroutes to the destination IP, reverse resolving, and using pattern matching to search for possible city, state, country names contained in the reverse DNS mappings of the hops nearest the target. (Since providers sometimes include state and/or city names in router rDNS hosts) On the other hand, it's perhaps the best geolocators can _try_ to do... Short of geolocation services manually calling ISPs and asking.../ making deals with major ISPs to procure lists of geographic regions and assigned IPs in those regions. I suppose that in theory proper geolocation close to 95% of IPs for page access requests would occur then (provided 95% of page access requests came from providers they had that type of direct information from) -- -J