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What do the cookie buttons change?

Cookie banners ask you to accept different kinds of cookies. Switch them on and off to see what each kind stores, and who can read it.

A simulation: this page sets no cookies.

Cookie choices

Cookies stored in this example

  • session=… · read by this site only
  • _stats=… · read by the site's analytics company
  • ad_id=… · read by an ad company, on every site it is on

Can another site recognise you through these cookies?

Yes: the ad company can read its cookie on any site where it runs. That is a third-party cookie.

What the sources say

  • A cookie is “a small piece of data a server sends to a user's web browser”. A cookie from a different site than the one you're on is a third-party cookie, and third parties can combine what they collect “to create a detailed profile of a user's browsing history” (MDN, Mozilla's web documentation).
  • Safari: Apple's tracking prevention “by default blocks all third-party cookies”. Firefox on computers gives each website a “separate 'cookie jar'” by default.
  • Refusing cookies doesn't stop everything: the W3C says clearing cookies or using a VPN does “not prevent further correlation”.
  • In California, you have “the right to opt-out of the sale or sharing” of your personal information, including with Global Privacy Control, a browser setting that covered businesses “must” honor as a valid request (California Attorney General).
Sources (6)Where each fact comes from