https://doi.org/10.1017/9781108890960 Published online by Cambridge University Press

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Daphne Keller & Paddy Leerssen

Act (CDA), which grants platforms unusually broad immunities, even when
they become aware of unlawful content, for the express purpose of encouraging
them to moderate and weed out “objectionable” content.3

Second, most intermediary liability laws give platforms obligations once they
“know” about illegal content. In much of the world, platforms that learn about
material like defamation or terrorist propaganda on their services must take
down that content or face legal consequences. Laws vary substantially,
however,
in what counts as “knowledge.” Under some national rules,
platforms can only be legally required to take down users’ speech if a court
has adjudicated it unlawful.4 Elsewhere, the law leaves platforms to decide for
themselves what speech violates the law.
Social_Media_and_Democracy