In their conclusion, the researchers — José González Cabañas, Ángel Cuevas, and Rubén Cuevas — state that one of the reasons Facebook keeps a record of its users interests is to
improve ad preferences, meaning that the company is «commercially exploiting sensitive personal data for advertising purposes.»
Among other things, the use of cookies enables us to
improve our Site by seeing which areas and features are most popular; to count the number of computers accessing the Site; to personalize the Site and
improve the Site experience; to record your
preferences and track the
ads you view; to track your transactional information; and to allow you to visit the Site without re-entering your member ID and / or password.