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How the heck does Facebook know where I live, when I have never provided anything about my address (or even city) to Facebook (or such companies)?
(My correct city was in the "anonymous" Sponsored "survey".)

(Also, slightly unrelated: Where is the best place to report this privacy violation?)

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3 Answers 3

up vote 15 down vote accepted

It will almost certainly use your IP Address to locate the general area of where you live. It is quite a common thing to do these days.

There are many services that can provide this information, a simple Google search returned http://www.ip2location.com/


Taken from this Wikipedia article on Geolocation Software

The primary source for IP address data is the regional Internet registries which allocate and distribute IP addresses amongst organizations located in their respective service regions:

  • American Registry for Internet Numbers (ARIN)
  • RIPE Network Coordination Centre (RIPE NCC)
  • Asia-Pacific Network Information Centre (APNIC)
  • Latin American and Caribbean Internet Address Registry (LACNIC)
  • African Network Information Centre (AfriNIC)

Secondary sources include:

  • Data mining or user-submitted geographic location data. For example, a weather web site might ask visitors for a city name to find their local forecast. Another example would be to pair a user's IP address with the address information in his/her account profile.
  • Data contributed by internet service providers.
  • Merging databases from different suppliers.
  • Guesstimates from adjacent Class C range[2] and/or gleaned from network hops.

Accuracy is improved by:

  • Data scrubbing to filter out or identify anomalies.
  • Statistical analysis of user submitted data.
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Related: Try using an anonymity network like Tor to disguise your IP if this is a concern for you. –  micah Jun 23 '11 at 19:24

They are not only targeting you IP address as @Barry pointed out but they may also use more information they gathered from you such as:

  • The location your friends provided (or even friends of friends)
  • Local pages you liked or commented on
  • Places you checked in
  • Coupons you used
  • Information on your profile such as your job
  • Comments or messages by you or someone else containing a city, region or even local business
  • Maybe even information found via search engines
  • Maybe websites you visited containing a facebook like button

(note that this is not officially provided by Facebook and is just brainstorming what might be used to determine your location)

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Try connecting from a different country/continent and see what happens: they will tell you that you are not connecting from your usual location and ask to go through some security checks to confirm that is really you, which basically means they log your geo-location coordinates every time you make login.

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