“This is a case about minor Plaintiffs’ alleged addiction to Defendants’ social media platforms and the alleged adverse effects flowing from that addiction.” That’s how California Superior Court Judge Carolyn B. Kuhl recently distilled about three years’ worth of litigation involving more than 1,000 coordinated cases from across the nation, as jury selection—barring last-minute delays or further settlements—starts on January 27 in the first bellwether trial.

The trial’s outcome in her Los Angeles courtroom may influence how the other consolidated personal injury cases—with potentially billions of dollars in collective liability at stake—are litigated. A series of pro-plaintiff verdicts, if upheld on appeal, would almost certainly result in some settlements and influence the future of some social media platforms, including how they are designed and deliver content to minors.

The bellwether trial marks the first time in the United States that a case alleging social media addiction will reach a jury, with plaintiffs’ attorneys and those for defendants ByteDance (TikTok), Google (YouTube), and Meta (Facebook and Instagram) finally getting to test their arguments before a group of citizens. Defendant Snap (Snapchat) settled the opening bellwether case earlier this week. Jury selection may take several days, “with 75 potential jurors expected each morning and afternoon through at least January 29,” and substantive questioning during voir dire beginning January 30 or later.

Known as K.G.M., the inaugural case is one of three scheduled bellwether trials in Joint Council Coordination Proceeding (JCCP) 5255, a massive collection of lawsuits I first addressed in late 2023. In November 2025, Kuhl greenlighted the trial on negligence and negligent failure-to-warn theories when she denied the defendants’ motions for summary judgment and summary adjudication. The JCCP is distinct from the federal multi-district litigation proceeding in Oakland, California, that I recently described. There, Judge Yvonne Gonzalez Rogers is scheduled to hear summary judgment motions on January 26 in social media addiction cases filed by six public school districts.

K.G.M. involves “a 19-year-old woman from Chico, California, who says she’s been addicted to social media for more than a decade and that her nonstop use of the platforms has caused anxiety, depression and body dysmorphia.” She allegedly “started watching YouTube at the age of six” and “obtained an Instagram account at 11, subverting the app’s age verification system. Two years later, she started using Snapchat. At 14, she started using TikTok.”

Here are some important matters to consider as the case starts.

Causation. Jurors must resolve several questions regarding causation, most importantly: What caused K.G.M.’s alleged injuries—design features of the platforms that supposedly addicted her or the third-party content of other users that she viewed? If the jury determines that the features of a specific platform (or platforms) were negligently designed to (and did) foster her compulsively harmful usage, that would be a win for K.G.M. Design features in question include infinite scroll, autoplay, and appearance-altering image filters.

Conversely, if the jury decides it was the content of others that she watched on a defendant’s platform that supposedly harmed her, it would be a momentous win for that defendant. Why? It would trigger First Amendment free-speech protections, as well as the platform’s general immunity from liability due to third-party content under the federal law known as Section 230.

Other key causation questions involve parceling out what (or how much, if any) harm may have been caused by which platform, whether warnings truly would have prevented the causation of alleged injuries, and whether something other than a platform caused the problems K.G.M. allegedly suffers.

Tech Leaders’ Testimony. Kuhl ruled in October that Meta founder, chairman, and CEO Mark Zuckerberg, as well as Adam Mosseri (head of Instagram), can be compelled to testify at the first trial. In rejecting efforts to prevent their appearances, Kuhl reasoned that “the testimony of a CEO is uniquely relevant, as that officer’s knowledge of harms, and failure to take available steps to avoid such harms could establish negligence or ratification of negligent conduct.” Their testimony will grab headlines.

Expert Testimony. Jurors will hear from expert witnesses testifying on K.G.M.’s behalf, including testimony about data, warnings, and causation. The defendants’ attorneys will question their assertions; whether expert testimony proves more helpful than confusing may be important.

Intangibles. The jurors, who will have some anonymity, must set aside their: (1) potential antipathy toward “Big Tech,” (2) possible preconceived opinions of the defendants as deep-pocketed corporations that can easily afford to pay substantial damage awards, and (3) empathy for minors supposedly harmed by those same corporations’ platforms. This may not be easy for some jurors, but they must do so and decide the case based only on the law and admissible evidence.

Ultimately, the stakes for the parties in K.G.M., as well as for First Amendment speech rights and minors’ safety, are enormous.