Mike said:
I often find pop up windows from 'Friendfinder' or something who tell me
that there are people in my village who are "looking for me" [1]. How do
they know the name of my village? My exchange is 4km away in a
differently named town, my domain is registered with a company based in
scotland. There are no servers, exchanges or anything else techy in the
village. Sometimes the ads say Brighton instead, though.
Several ways. Firstly there are big databases of IP addresses, such as
Maxmind GeoIP. You can try out their service here:
http://www.maxmind.com/app/lookup_city
Maxmind gets their information from a variety of sources -- mostly by
buying data from online retailers. The retailer records your delivery
address and your IP address, which gives it a rough guess of where that IP
is located -- sure you might be ordering something to be delivered to a
different address, but with GeoIP averaging out the data over thousands of
data sets, they end up with reasonably accurate results.
They claim to be 99% accurate at country-level, and 81% accurate at city
level in the US (only 54% in the UK, varies in other countries -- by
"accurate at city level" they mean "within 25 miles of the city"). They
also offer a free version with slightly less accuracy, but still good
enough for advertisers of the type you mentioned.
Both the free and paid for versions give me my IP address in Maidstone,
Kent, which is probably outside their 25 mile range (I've not bothered
measuring the distance), but not a million miles away either. (I live
about 20 miles from you -- in Lewes.)
Some sites seem to believe I live in Popham, Hampshire -- not sure which
database they use, but probably one of Maxmind's competitors.
Another option is to run a whois query on the IP address. For larger
offices who actually manage their own IP space, this should give them the
full office address. For most home users at ISPs this end up returning the
ISP's head office address, or perhaps a slightly more accurate address,
such as a local telephone exchange. Some ISPs allow home users to manage
their (static) IP addresses and provide proper whois information. Running
a whois on my IP address at whois.ripe.net gives my correct address and
postcode.
--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.17.14-mm-desktop-9mdvsmp, up 21 days, 19:20.]
Bottled Water
http://tobyinkster.co.uk/blog/2008/02/18/bottled-water/