Why does every website ask about cookies?

Dan is buying hiking boots. He finds the pair, puts them in his cart, and up pops a banner: “We use cookies.”

He clicks “Accept all” without reading it, the way he always does. Then he stops.

“Why does every website ask?”

“Follow your cart,” says Liz.

A cookie is a little note

When Dan put the boots in his cart, the shop left a small note in his browser (the app he uses to visit websites). Each time he comes back, his browser hands the note back to the shop, and the shop remembers what's in his cart.

That note is a cookie. Often it doesn't even hold the boots: it holds a code, and the shop keeps the cart on its own computers, under that code. Either way, the note is how the shop knows it's him.

Cookies like this one are useful. They keep your cart full, keep you signed in, and remember that you wanted the site in English.

Some notes follow you

But the shop isn't the only one leaving notes.

Most websites include bits of other companies: an ad here, a “like” button there, a tracking code nobody sees. Many of those come from the same few ad companies, hidden on thousands of sites. Each one can leave its own note in your browser and read it back on every site where it's hidden.

So the ad company sees Dan on the boot shop. Then on the recipe site. Then on the news site. And that's how it happens: Dan's boots show up as an ad everywhere he goes.

“My boots ad! It's everywhere!”

Those are the notes the banners are really about.

Why sites have to ask

In the European Union and the UK, the law says a website may only leave notes in your browser if you agree first. There's one big exception: notes the site needs to do what you asked, like your cart or your sign-in.

That's why the banner exists, and why you see it everywhere, not just on European sites: many sites outside Europe have European visitors, and showing one banner to everybody is simpler.

Since February 2026, the UK also lets sites skip the question for some site statistics and remembered preferences, as long as you can say no. Advertising notes still need your yes in both places.

What “Reject all” does

Dan worries: “If I say no, do I lose my cart?”

No. “Reject all” still lets the site keep the notes it needs, like your cart and your sign-in. Europe's privacy regulators use exactly those two as examples.

A few things to know, though:

• Rejecting keeps new notes out. It doesn't erase old ones. If you clicked “Accept all” last week, those notes are still in your browser until you delete them or take your yes back. The law says taking it back must be as easy as giving it, and many sites have a “cookie settings” link at the bottom of the page.
• Some extras may wait for your yes. Embedded videos, maps and social posts come from other companies, with their own cookies. Many sites show a “click to load” box instead until you agree.
• Badly built sites sometimes break. If a site files the cookie it really needs under “marketing”, rejecting can break the sign-in or the checkout. That's the site's mistake, not the law.

What a site can't do

In the EU, a site isn't supposed to lock you out for saying no. A page that shows nothing until you click “Accept” is what regulators call a cookie wall, and they say a yes given that way doesn't count.

“Accept or pay”, where a news site offers tracking or a subscription, is less settled. Regulators say the biggest platforms mostly can't rely on it, but the rules for other sites are still being argued.

Your browser already helps

The notes that follow you around are called third-party cookies, and browsers treat them differently:

• Safari has blocked them by default since 2020.
• Firefox gives each website its own cookie jar, so a note left on one site can't be read on another.
• Chrome still allows them. Google planned for years to remove them, then decided in 2025 to keep them, as a setting you can change.

So on Chrome, the banner is still doing real work.

Back to the boots

Dan's next shop is a hat shop. The banner pops up. This time he clicks “Reject all”, puts a wool hat in his cart, and his cart still works.

His conclusion: a cookie is a little note in his browser. Some help. Some follow him. Now he knows which button keeps which.

What you can do

• Click Reject all when you don't need a site's extras. Your cart and sign-in still work.
• Already accepted? Look for a cookie settings or privacy choices link at the bottom of the site, and change your answer there.
• On Chrome, block the notes that follow you: Settings → Privacy and security → Third-party cookies → Block third-party cookies. A few sites may ask you to sign in again.
• To clear one site's notes in Chrome: Settings → Privacy and security → Third-party cookies → See all site data and permissions, search for the site, then Delete.
• If a site breaks after “Reject all”, try its cookie settings and allow only what it calls necessary or functional.