TL;DR: As Mechanical Turk became gamed by bots, Prolific built a provenance-first worker marketplace for academic research with longitudinal records of personality, demographics, and cultural fluency. That data is now its bet for the next wave of AI training, the companion, therapist, and education use cases where human personality matters more than credentials. Sacra estimates Prolific hit ~$350M in annualized revenue in April 2026. For more, check out our full report and dataset on Prolific as well as our interview with COO Jemma White...