How do sites get my city?

[Humbocchio]

There are ads and such on some websites that include my city's name, even though I never told them my city. Example: "Singles in X are looking for you" and generic things like that. How could they know, and are there any threats related to it?

[Anand S]

All your searches will be bound to your location by the IP address. for example if you try searching in Google too, it automatically give reference related to your search. no threat behind this.

[Ermir]

Its the IP adress buddy.
I reccomend you disabling those ads by using AdBlock Plus. it is a great software.

[Yeti]

You reveal your IP address to any website you visit, and since they're assigned in blocks to various ISP's, etc., they can usually pinpoint you to at least your city. Some browsers also have a geolocation switch you may need to set to "off" to not reveal more precise information.

And if you feel uncomfortable with that, you should probably be aware that when Google has driven around photographing streets for Google Maps, they've also picked up data on which wireless networks are functioning in any given area (called Google Location Services). Now, if you use a cell phone with Google services on it (like Google Maps, as most people have), they can rapidly know where you are within something like 50 feet just by recognizing which wireless networks are in the area around you (operating out of homes, businesses, etc.). And when you realize that operations like Google and Facebook are also developing massive network "maps" of who's connected to whom, it can get a little scary just how much they're able to monitor about you, and how much they could even "infiltrate" your social network if they wanted to influence you, or plant a product for you to buy, etc.

Anyway, there aren't any major known threats from revealing your IP address and related info (beyond someone being able to rapidly make up ads that appear directed at you), but you should probably be aware that whatever site you visit can get a decent amount of info like that from you (including what computer browser and operating system you're using, what your display dimensions are, and so on). And I'd seriously be more concerned about what exactly you're potentially revealing to whom in the big scheme of things if you start putting up personal information any place like social networks, even if you think it's "private."

[Intellectualwinter877]

When your ISP establishes a block of IP Addresses, they need to obtain certain registration details in order to proceed. The registration details are stored publically, and relate to your Internet provider alone. For example, my Internet provider is based on Chatham, Ontario, Canada, and while I live in Toronto, I receive a lot of offers that come from Chatham.

Occasionally, I might get offers closer to home. In those cases, it's likely because I filled out a form on a website that was tied into that advertising network, who now uses the corrected information to directly advertise to me. Since every Internet request includes a destination to service those requests, it's not technically possible to stop it unless you're behind a proxy-enhanced software package such as Tor.

I hope that explains it well enough!