• Votes federate, but only for communities followed. I won’t see your votes in a community that I don’t follow, but I can see when you upvoted or downvoted what post in the community.

    A scraper could simply follow every community on a Lemmy server and, barring Lemmy performance issues, will receive all comments and votes.

    Just a quick and dirty SQL query of which votes of yours are in my server’s database:

    select comment_like.score as score,comment_like.published as when, person.actor_id as who, comment.ap_id as what from comment_like join person on person.id = comment_like.person_id join comment on comment.id = comment_like.comment_id where person.actor_id = 'https://lemmy.ml/u/GolfNovemberUniform' order by comment_like.published desc; 
    

    The same info is also available for posts, of course, I just didn’t want to bother making the query any longer.

    Server admins/mods on Lemmy also have a button to see who upvoted and downvoted each post. This is just the inverse of that.