How do sites get my city?

[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!