Supercookies and Evercookies

The tracking industry keeps inventing more persistent methods. Supercookies are stored in spots that standard cookie-clearing tools miss — HTML5 local storage, IndexedDB, or even cached images and ETag headers.

Safari blocks third-party cookies by default. Firefox takes a different default approach: Total Cookie Protection isolates cookies in a separate jar for each site, so a third-party tracker cannot reuse the same cookie across the web. Both reduce cross-site tracking, but they do it through different mechanisms.