Defining it's tricky, and it is hard to see how to do it algorithmically. But that doesn't mean it's impossible. I think Reddit does something interesting wit

Defining it's tricky, and it is hard to see how to do it algorithmically. But that doesn't mean it's impossible. I think Reddit does something interesting with upvote / downvote ratios, I don't remember the specifics. It might also be the case that toxic content spreads differently, or there's some other measurable way to separate it. Data and experiments to measure user behavior will probably be needed to develop an algorithm.