California Gov. Gavin Newsom announced Tuesday that he signed a first-of-its-kind bill into law requiring social media companies to be transparent about their policies on hate speech, harassment, extremism and disinformation.
The measure, AB 587, will also require the companies to report data on the enforcement of the policies.
"California will not stand by as social media is weaponized to spread hate and disinformation that threaten our communities and foundational values as a country," Newsom said in a statement. "Californians deserve to know how these platforms are impacting our public discourse, and this action brings much-needed transparency and accountability to the policies that shape the social media content we consume every day."
"Social media has created incredible opportunities, but also real and proximate threats to our kids, to vulnerable communities, and to American democracy as we know it," Assemblymember Jesse Gabriel, the bill's author, said.
"This new law will finally pull back the curtain and require tech companies to provide meaningful transparency into how they are shaping our public discourse, as well as the role of social media in promoting hate speech, disinformation, conspiracy theories, and other dangerous content," he added.
While the bill had bipartisan support, its opponents have said companies already have to make their content moderation policies public and objected to requirements to disclose sensitive information to the state attorney general.
Some of those opponents include the California Chamber of Commerce, Computer and Communications Industry Association, Consumer Technology Association, Internet Coalition, NetChoice and TechNet.
Last year it had stalled over free speech issues.
The legislation was sought by the Anti-Defamation League and other groups, which said the measure is key to combatting online hate speech.
The Associated Press contributed to this report.