alt Hacker NewsEdit: it just occurred to me that the book describes a kind of filter bubble, too. The Palantir stones are inherently incapable of showing false data. But they became tuned over time to show highly editorialized video clips which supported a specific (Evil) narrative. That (IIRC) included future projections of possible outcomes.
Denethor (?) tried to use a Palantir for good, but went mad after viewing its selections for years.
Denethor was allowed to see what Sauron wanted him to see and nothing more, because he lacked the ability to control the stone away from Sauron. The parallel falls apart somewhat since here his access was essentially controlled by a third party.
(you might argue it reflects certain social media outcomes ofc)