It tracks karma, automatically collapses replies and hides threads based on downvote thresholds and attaches icons to usernames to tell other users in advance that they have been downvoted in the past. And alongside that, votes are hidden. So a few determined users (or even one determined user and a few bots) can easily silence other users or even effectively censor content just by mass downvoting.
Just like Reddit, and notably NOT like the rest of the threadiverse which has done away with karma, doesn't auto-hide downvoted users or content snd makes votes public.