As part of Mozilla's emphasis on user privacy, features intended to limit user tracking have come to Firefox, but are not yet enabled by default.
With the release of Firefox 63, Mozilla has included enhanced privacy protections as part of the non-profit organization's renewed approach to limiting the ability of advertisers to track individual user behavior across websites.
In August, Mozilla announced their intent to change the default behavior in Firefox to limit third-party tracking, citing data breaches such as the Facebook data privacy scandal. Mozilla's objection to this behavior is on the basis that this "data that can be used to subtly shape the content you consume or even influence your opinions."
The new version of Firefox now gives users the option to block cookies and storage access from third-party trackers, which is intended to block common forms of user fingerprinting and tracking across websites...more via TechRepublic