What is Cookie?
A small file websites store in your browser. Some remember your login; 'third-party' ones track you across different sites for advertising.
First-party cookies are mostly useful — they keep you logged in and remember preferences. Third-party cookies are placed by advertising networks embedded in the page and let them follow you across the web, building an interest profile. Blocking third-party cookies in your browser settings, and clicking 'Reject all' on consent banners, are the two easiest tracking reductions available.