I received an email from a reader wanting to know why many retail websites he visits pop up a dialog box wanting to access his location. He said he never allows it, but he wants to know why they ask.

I can think of a lot of reasons.

Some of the bigger companies will even tell you why they are asking.

For example, I visited the Whole Foods website, and as soon as I searched for a product (salmon), I was greeted with a pop-up dialog asking my location.

The dialog said: “Find in-store pricing, weekly sales, and local products by selecting your store below.”

These are all good reasons for wanting to know my location. If I want to see the price for salmon in my neighbourhood, I’ll need to tell Whole Foods my location.

You don’t have to tell them your home address, but they do want to know what store is closest so they can show exact pricing.

When I searched for salmon and didn’t give them my ZIP code, they showed a variety of salmon offerings. But when I did choose a store based on my ZIP code, the number of salmon items got smaller - not all were offered in my store - and the prices appeared.

I’m my younger days I worked for a grocery store chain, and I can tell you prices are not the same in every store in the company.

I changed my Whole Foods store from my Texas location to Beverly Hills, California, and the price per pound for Atlantic salmon was US$1 per pound more expensive.

Many retail websites can also let you know if items are in stock at a specific store.

This last Christmas, I wanted to buy a sweatsuit for my niece. The style and colour was not available in my closest Target store, but on their website, I was able to see it was available in a store just a few miles away.

I had to give them my ZIP code so they could show me the closest stores and the real-time inventory.

Of course, stores also want your location data so they can gather as much information as they can about you.

Even if you don’t give your location, websites have a pretty good idea where you are based on your device’s IP address, which is your phone or computer’s Internet Protocol address, which is assigned by your Internet provider.

With location data, along with cookies and other browsing data, websites can harvest a lot of information about you. They use this information to try to sell you things. That data might even be shared with other companies.

I’m sure you’ve noticed the pop-up notifications on websites asking you to allow cookies, which are ways websites can use your browser to track your web activity.

This is a much larger topic than I have room to address here. I found a nice explainer of location tracking and sharing from Mozilla, the maker of Firefox. It also includes instructions on how to turn off location sharing. You can read it at https://blog.mozilla.org/en/privacy-security/location-history.

 - TNS