Big Tech CEOs plan to defend their services against accusations that they have failed to root out hate and anti-vaccine hoaxes when they testify before Congress on Thursday.

“People want to see accurate information on Facebook, and so do we,” CEO Mark Zuckerberg says in written testimony submitted ahead of the hearing to the House Energy and Commerce Committee, which is examining social media’s role in promoting extremism and misinformation. “That’s why we have made fighting misinformation and providing people with authoritative information a priority for the company.”

Many lawmakers from both parties want to crack down on Big Tech companies, which they say have become too powerful. They point to how extremists have used social media services to organize things like the U.S. Capitol riot in January or how anti-vaccine activists have spread misinformation about COVID.

In response, the CEOs will stress that they will continue trying to eliminate harmful posts, though they admit their systems are imperfect. They will also emphasize the good their services do.

Zuckerberg, a frequent congressional punching bag in recent years, will voice support for updates to Section 230, the law that protects Internet services from being held liable for what their users post. Lawmakers, many of whom are upset by social media companies’ lax policing, have suggested changes to the law, including repealing it altogether.

Instead of granting companies immunity, Zuckerberg’s statement says, Congress should require them to prove that they have “adequate” systems, dependent on the service’s size, that identify and remove problematic content. However, he notes, companies should face no liability if some posts slip through—a position that protects Facebook from consequences for missing problematic posts.

“Platforms should not be held liable if a particular piece of content evades its detection—that would be impractical for platforms with billions of posts per day,” Zuckerberg says.

Meanwhile, Sundar Pichai, CEO of Google parent company Alphabet, will caution legislators against changing Section 230. Without the current protections, Pichai claims, Internet services would be forced to “over-filter” content or not filter content at all, “harming both free expression and the ability of platforms to take responsible action to protect users in the face of constantly evolving challenges.”

Twitter CEO Jack Dorsey, based on his testimony, appears to be the most conciliatory by admitting that public trust in social media services like Twitter is waning and then saying that his company intends to reverse that trend.

“As we look to the future, I agree with this committee that technology companies have work to do to earn trust from those who use our services,” says Dorsey, who for years has said much the same thing in response to criticism.

The CEOs appearance before Congress is just the latest in a string of hearings in recent years in which they have participated. They have testified about election integrity issues, antitrust concerns, and Section 230.

Hoping to downplay Facebook’s role in spreading misinformation, Zuckerberg will hammer home the point that most people use the social network to stay connected, “share ideas, have fun,” and “offer support.” He will also emphasize that “the vast majority of what people see on Facebook is neither political nor hateful.”

Dorsey discusses his company’s focus on increasing transparency around Twitter’s moderating decisions, which the executive believes is one reason users may distrust the service. He will also speak about ensuring that users have a straightforward appeals process for any blocked posts, a message aimed at countering criticism from conservatives who say their views are being unfairly censored.

Dorsey also touts Twitter’s work on two of its newest projects: Birdwatch aims to tackle misinformation with help from users. And Bluesky aims to create a decentralized form of governance for social media companies, similar to that of cryptocurrencies, which would remove some of the onus on companies like Twitter to be solely responsible for difficult enforcement decisions.

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