Dropsitenews published a list of websites Facebook uses to train its AI on. Multiple Lemmy instances are on the list as noticed by user BlueAEther
Hexbear is on there too. Also Facebook is very interested in people uploading their massive dongs to lemmynsfw.
Full article here.
Link to the full leaked list download: Meta leaked list pdf
If you put ANYTHING on the internet, you can expect it to train AI. It does nt matter where…unless you go to a site that actively makes it hard to do so or has a passcode. Scrapers only work if its cheap to do so.