We are all used to ads that follow us around. You click on something or do a google search, and for days afterwards you get shown advertisements for similar items. But here is something much odder.

I have a Yahoo address which I give to businesses that demand an email address. It acts as a kind of honeypot for spam, but some useful things like Spectator updates also go there. So once a day, I drop in to clear the inbox and read the latest news.

Lately I have seen a lot of ads for local services in Antrim, Northern Ireland. There's a will-writing service which pops up quite often and today I saw a fashion and fitting service ad. Now obviously if I lived in or near Antrim, these things might be of interest to me, but I don't. So why does Yahoo think I do?

uBlock Origin + AdBlocker Ultimate

I don't get much in the way of ads.

I don't really mind the ads; I just ignore them. But I'm genuinely curious as to why advertisers seem to have located me in the wrong place.

Using uBlock Origin will do exactly the same thing, except you also save bandwidth and reduce memory from them not loading in the first place, as well as having the added benefit of being more protected from malware and phishing.

Though this is for web-based adverts; if they're email-based adverts then other tools apply, and the potential reasons for adverts being based on wrong location are different.

Thanks for that. Saving bandwidth is important to me as you know. I just popped over to Yahoo and the difference is amazing.

Wait, how old do they think you are?

How the heck would I know that?

I don't know how their geolocation works but can say that it is all quite inaccurate and I am often placed up to 200km away and usually 25 km away from the real site.

That said, when possible, blocking javascript does away with the worst of the worst. Ads don't in and of themselves need javascript but those that do get blocked along with the malware and some of the surveillance.

Yes, I always have noscript running.

I found this very interesting article which explains it. Phones of course are easy to locate because they have to broadcast their position to the telephone masts, but for static computers they use paid-for data from third-party databases of IP addresses "mapped by years of data mining". Of course that is subject to GIGO like everything else and at best, it gives the ISP's server location, not yours. Apparently it's reasonably accurate about your country, rather less so about towns.

Turn scripts, images, plugins off in your browser. Then clear all cookies. You could even use dillo.

Go to https://www.google.com/
Search for something, then look at the bottom of the page. They have you fixed by IP address. Right down to your zip code.

Or do this. Get that url that google makes after a search, and paste it into curl

Such as:
Now open goog.html in your web browser.

They know where you are. And apparently they want you to know that they know

I used links and it said Blackpool! Not very impressive. There's a link to a page of explanations.

Must be the ISP or web infrastructure in your part of the world. They get me to the correct US zip code even, and town.

Sure. It's part of their service package:
Personalised everything, your map position, restaurants you might want to visit, products you are interested in...
Most people quite seriously and unironically see it as luxury, not surveillance.

A good hosts file will help.
https://someonewhocares.org/hosts/
Periodically, I download (save the link as) the file, edit it to remove the hash mark in front of several addresses and then copy it, simply as, hosts, to /etc (as per the instructions at the top of the page).