evidence: And tennis star Rafael Nadal isn’t the only one posting these types of "opt out" posts, trying to stop Meta from using their content to train its A.I. models with hundreds of thousands of similar posts appearing online over the past week. [...] So yes, Meta can use, and is using your public posts to train its evolving A.I. systems. [...] Other than that, no, you can’t stop Meta using your content to train its A.I. models, unless you delete your content, or mark everything as private or friends only. And that only works from now on, you can’t do this retrospectively.