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A California jury weighing claims that major social media platforms harm young users heard striking testimony this week: internal data indicates the teenage plaintiff in the case was shown more than 17,000 advertisements on YouTube in a single year.

The testimony came during a high-profile bellwether trial in Los Angeles County Superior Court, one of the first cases selected from thousands consolidated against companies including YouTube, Instagram, TikTok and Snapchat. The lawsuits allege that certain platform features were intentionally designed to encourage compulsive use among minors.

YouTube Executive Testifies

Cristos Goodrow, a YouTube vice president involved in shaping the platform’s recommendation systems, returned to the witness stand for a second day. Attorneys questioned him extensively about usage data and design features such as autoplay and short-form video feeds.

During cross-examination, plaintiff’s attorney Mark Lanier presented what he described as a company-produced document showing the young plaintiff — identified in court as Kaley G.M. — was served 17,122 ads over a 12-month period.

Goodrow acknowledged that the document appeared to reflect that number. That total would average out to more than 1,000 ads per month.

Lanier suggested the figure implied extensive time spent on the platform. Defense counsel, however, emphasized that the ads were not limited to the short-form “Shorts” feature and could have been delivered across the broader YouTube ecosystem.

Dispute Over Screen Time

YouTube’s legal team told jurors the plaintiff averaged roughly 29 minutes per day on the platform between 2020 and 2025. Of that time, about four minutes reportedly resulted from autoplay and approximately one minute per day from Shorts usage.

If the 29-minute daily average is accurate, that would total about 10,585 minutes annually. Dividing the ad total across that viewing time suggests roughly 1.6 ads per minute.

Lanier has argued that the numbers raise questions about the accuracy of YouTube’s time-tracking data and indicated he intends to revisit the issue during continued proceedings.

A YouTube spokesperson did not immediately comment on the specifics of the document discussed in court.

Broader Allegations Against Social Media Platforms

The bellwether trial is the first in a series of cases consolidated before Judge Carolyn B. Kuhl. The outcome could influence settlement discussions in thousands of related lawsuits.

The plaintiffs claim that major platforms deliberately incorporated features such as infinite scrolling, autoplay, push notifications and algorithmic reward systems that encourage prolonged engagement among minors. Companies deny the allegations.

TikTok and Snap have reportedly resolved claims with this particular plaintiff, though broader consolidated cases remain active.

Pretrial rulings narrowed the issues jurors will consider. The focus is not on third-party content posted to the platforms, but rather on whether the platforms’ design features themselves are addictive or negligently implemented. The companies face claims including failure to warn, negligence and concealment.

Advertising Revenue and Youth Users

Testimony also included discussion of a 2023 peer-reviewed academic study estimating that social media companies generated billions of dollars in advertising revenue from users under 18 in 2022. A data science professor called by the plaintiff stated he believed the study’s methodology was sound, despite defense questioning about its funding sources.

Cross-examination on that topic was ongoing when court adjourned for the day.

What Comes Next

The plaintiff, now 20, alleges that excessive social media use during her youth contributed to mental health challenges. Her legal team has indicated she may take the stand soon.

With billions of dollars potentially at stake for technology companies, the trial is being closely watched by the legal and tech industries alike. The jury’s findings in this first case could help shape the trajectory of the broader litigation over how digital platforms design their products — and how much responsibility they bear for young users’ well-being.