Julianna Arnold (at microphones), parent and plaintiff in the case, speaks outside the Los Angeles Superior Court during the social media trial tasked to determine whether social media giants deliberately designed their platforms to be addictive to children, in Los Angeles, on February 18, 2026. Meta CEO Mark Zuckerberg on Wednesday said he regretted the slow progress his company made in identifying underage users on Instagram as he testified at a landmark social media addiction trial in Los Angeles. Zuckerberg was the most hotly anticipated witness in the California trial, the first in a series of cases that could set legal precedent for thousands of lawsuits filed by American families against social media platforms. (Photo by Patrick T. Fallon / AFP via Getty Images)