Mark Zuckerberg took the witness stand in a packed courtroom on Wednesday as part of an unprecedented social media trial examining whether Meta Platforms’ platforms deliberately addict and harm young users.
The high-stakes case centres on a now 20-year-old woman, identified in court documents as KGM, who alleges that her early use of Instagram contributed to depression and suicidal thoughts. Meta and YouTube, owned by Google, are the remaining defendants in the lawsuit after TikTok and Snap settled earlier.
The trial is being closely watched as it could shape the course of thousands of similar lawsuits across the United States.
Plaintiff alleges addiction and harm
Attorneys representing KGM argue that social media companies knowingly designed their platforms to be addictive, especially for vulnerable teenagers. They claim that the plaintiff became hooked on the technology at a young age, which worsened her mental health struggles.
Opening his questioning, plaintiff’s lawyer Mark Lanier framed the debate starkly, saying companies faced three choices when dealing with vulnerable users: help them, ignore them, or “prey upon them and use them for our own ends”.
Zuckerberg responded that a reasonable company should aim to help its users. “I think a reasonable company should try to help the people that use its services,” he said, adding that he rejected the implication that Meta exploited vulnerable individuals.
Meta’s legal team has acknowledged that KGM experienced mental health issues but disputes that Instagram was a substantial contributing factor. Defence attorneys pointed to medical records referencing a turbulent home environment and argued that the plaintiff used social media as a coping mechanism rather than being harmed by it.
Exchanges over compensation and charity
Lanier also questioned Zuckerberg about his personal wealth and philanthropic pledges. The Meta chief has previously committed to giving away “almost all” of his fortune, largely towards scientific research.
When asked how much he had pledged to victims allegedly impacted by social media, Zuckerberg replied, “I disagree with the characterization of your question,” maintaining that he did not accept the premise behind it.
The exchange underscored the tense and often combative tone of the courtroom proceedings.
Media training and ‘robotic’ persona
A significant portion of the cross-examination focused on Zuckerberg’s public image and alleged media coaching. Lanier cited internal communications suggesting that Zuckerberg had received advice on appearing “authentic, direct, human, insightful and real”, and avoiding coming across as “robotic” or “corporate”.
Zuckerberg pushed back, saying the comments were merely feedback rather than structured coaching on how to testify or respond to difficult questions. “I think I’m actually well known to be sort of bad at this,” he said of public speaking, referencing long-standing online criticism of his sometimes awkward media appearances.
The line of questioning sought to portray the Meta CEO as carefully managed in public settings, a characterisation he repeatedly rejected.
Debate over age verification and platform design
Another focal point was Meta’s age verification policy. Zuckerberg reiterated that the company restricts users under 13 and employs systems to detect those who lie about their age.
“I don’t see why this is so complicated,” he said during a lengthy exchange, defending the company’s safeguards for young users.
The plaintiff’s legal team is expected to probe further into Instagram’s algorithm, infinite scrolling features and cosmetic filters — tools they argue are engineered to maximise engagement and keep users hooked.
Last week, Adam Mosseri, head of Instagram, testified that he disagrees with the idea that social media use can constitute clinical addiction. He maintained that Instagram invests heavily in youth safety measures and that harming users would not serve the company’s long-term interests.
A bellwether moment for Big Tech
This trial is among three selected as bellwether cases, meaning their outcomes could influence how courts handle thousands of pending lawsuits against social media firms.
Bereaved parents, who believe social media platforms contributed to tragedies in their families, are expected to attend the proceedings. For Zuckerberg, this marks the first time he is answering such allegations before a jury, rather than in congressional hearings.
A Meta spokesperson said the company strongly disagrees with the claims and is confident that the evidence will demonstrate its longstanding commitment to supporting young people.
Meta is also facing a separate trial in New Mexico that began last week, underscoring mounting legal pressure on major technology companies over youth safety.
As testimony continues, the case is likely to test the legal boundaries of platform responsibility in the digital age. Its verdict could have far-reaching consequences for how social media companies design products and protect younger users in the years ahead.