For Doe, he was “dismayed” to learn that complete and partial transcripts of chats discussing his family’s financial data were seemingly shared with Google and Meta, allegedly alongside PII. He relies on Perplexity to help manage his taxes, get legal advice, and make investment decisions, his complaint said. Without an injunction blocking Perplexity’s allegedly ongoing privacy harms, he will be blocked from using his preferred search engine, he complained.

Other users in the proposed class most likely turned to Perplexity when researching other sensitive topics, the lawsuit alleged. According to the lawsuit, the companies designed ad trackers to operate “surreptitiously” so that they could allegedly “exploit this sensitive data for their own benefit, including targeting individuals with advertising and reselling their sensitive data to additional third parties.”

Perhaps most troublingly, people frequently use such AI systems to research health and medical information, particularly when consulting with a human might be embarrassing or upsetting.

Supposedly capitalizing on users’ tendency to overshare with AI systems, Perplexity is seemingly trained to request that users upload sensitive records during chat sessions, the complaint said. That includes information that, if shared with Google and Meta, could result in users suddenly being targeted with advertisements that they “may find overwhelming, disturbing, or, in many instances, physically deleterious,” the complaint said.

For example, Perplexity responds to a basic prompt like “What is the best treatment for liver cancer?” by volunteering that “I can help you interpret a specific scan report, biopsy result, or proposed treatment plan if you share more details,” the complaint noted.

Among invasive trackers embedded in Perplexity’s AI search engine are the Facebook Meta Pixel, Google Ads, and Google Double Click, as well as possibly a technology that Meta calls “Conversions API,” the lawsuit said. Meta allegedly recommends that partners use that last technology in combination with the Meta Pixel, because it supposedly serves as a “workaround” that prevents “savvy users” from blocking Pixel tracking, his complaint said. Notably, Meta has been hit with several privacy lawsuits opposing that tech, with some settlements, while Congress has dinged some former partners who used trackers from Google and Meta.