Disabling third-party cookies
Another thing you can do to stop ad cookies is disable third-party cookies in your browser — though installing Disconnect or Ghostery has much the same effect.
In Safari, they’re actually disabled by default. In Chrome, you’ll have to go to Settings > Advanced > Privacy and Security/Content Settings > Cookies to find the switch to turn off third-party cookies. In Firefox, you have to go to Options > Privacy and select ‘use custom settings for history’ to see the option to disable them. In Edge, go to Options > Settings > Advanced Settings and select the option to Block on ‘Third Party Cookies’ under Cookies.