Location specific ads - How'd they do that?

I have noticed that some ads on the net are able to pinpoint a surfers location, like "People in Sometown waiting to meet you!"... now, I understand how they could get the ISPs city, but I see some that pinpoint it further, where "Sometown" is not the city where the ISP is located, but is correct for my location... I do not allow cookies, and do not fill out any forms with my location, I don't see any way that a website could ferret out this information with just an ip number to go by...



it seems that it is done using zip codes; say, my ISP is located in Bigtown, I also live in Bigtown, but right on the city limits, and my zip code is actually a Sometown zip... the ads will say "Sometown"... as I said, I don't fill out any forms, never enter my address or zip code in anything, no cookies, etc...



Anyone have an idea how this is done? and sorry for the silly place names :oPLocation specific ads - How'd they do that?
Your IP address tells them where you are.Location specific ads - How'd they do that?
Your computer has a unique address that is sent out so that whichever site you're connecting to knows where to send the data to. The software doesn't send out the data willy-nilly or you'd be receiving everyone's data, emails, streaming audio, etc. The computers' address is a sub-address to your ISP's address.

The system might not be able to tell which house you're in or which street you're on, but the software can tell the internet equivalent to a telephone number.



At least that's how I think it all works... :-)

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