From Electronic Frontier Foundation:

Lawsuits claiming that online services aid terrorist organizations just by hosting their content or having users who espouse the organizations’ views potentially could censor a vast amount of protected expression online, EFF and a coalition of other civil society groups argued in a brief filed this week…

Although the legal issues in Taamneh primarily center on how federal courts should interpret the ATA’s language,the Ninth Circuit’s broad interpretation would have dangerous implications for the First Amendment rights of internet users and the platforms hosting their speech, according to a friend-of-the-court brief filed by EFF, the Center for Democracy & Technology, the ACLU, the Reporters Committee for Freedom of the Press, the Knight First Amendment Institute at Columbia University, and the R Street Institute.

“These platforms and other intermediaries provide essential fora for speech and have become a primary source of news, information, and discussions across the nation and around the world,” the brief argues. But if the Ninth Circuit’s “startlingly broad construction of the ATA stands, online intermediaries will be forced to suppress protected speech…”