IN RE: SOCIAL MEDIA ADOLESCENT ADDICTION/PERSONAL INJURY PRODUCTS LIABILITY LITIGATION
Issue
In *In re: Social Media Adolescent Addiction/Personal Injury Products Liability Litigation*, Meta Platforms argues that the State Attorneys General cannot credibly claim surprise or prejudice from five of Meta's trial witnesses because the AGs' own October 2025 interrogatory responses demonstrate they had full notice of those witnesses' relevance and subject matter. The underlying legal question — whether Meta adequately disclosed these witnesses during discovery such that striking them is warranted — turns on the interplay between MDL case management orders, Rule 26 disclosure obligations, and the doctrine that a party cannot claim prejudice from information it already possessed.
What Happened
This is a Notice filed by Meta on June 4, 2026, at the pre-trial stage of the Social Media MDL in the Northern District of California, in connection with Meta's opposition to the State AGs' motion to strike five of Meta's witnesses from its trial witness list (ECF 3056). The filing attaches twenty exhibits, anchored by Exhibit J — the AGs' own Third Supplemental Interrogatory Response from October 2025 — which Meta deploys to show that the AGs had detailed knowledge of the contested witnesses' anticipated subject matter, including platform design, age verification, COPPA compliance, and data practices regarding users under thirteen. Meta simultaneously requests that the AGs' own supplemental filing (ECF 3104) be stricken as a reply-style submission filed without leave of court in violation of local rules. The filing is styled as a neutral Notice but functions substantively as a follow-up opposition brief, with the voluminous exhibit record marshaled to demonstrate that the five witnesses' anticipated testimony tracks issues the AGs themselves placed at the center of the litigation.
Why It Matters
This pre-trial skirmish over witness lists telegraphs the shape of the trial itself: the five contested witnesses are positioned to contest or contextualize the core claim that Meta designed its platforms with knowledge that they were harmful to children, which maps directly onto the negligent design and platform-own-conduct theories that remain unsettled across the broader § 230 landscape. Meta's strategy of deploying the AGs' own detailed interrogatory allegations to win a procedural point carries a notable risk — those same allegations describe Meta's purported knowing harm to minors in terms that may be difficult to cabin once introduced into the trial record for any purpose. For observers tracking how product-design defect claims against social media platforms will be tested against actual trial evidence rather than pleadings, this filing is a useful preview of the evidentiary terrain on which those doctrines will be litigated in what is among the highest-stakes platform liability proceedings currently in active pre-trial proceedings.
Related Filings
Other proceedings in the same litigation tracked by this monitor.
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