NUDGE THEORY IN ACTION, PART 94.
Reddit has developed a simple tool to prevent "vote brigading" from other subreddits, in which redditors who are not members of a community come in and mass-upvote or mass-downvote comments.
It's as simple as prefixing reddit URLs with np. when submitting them to reddit. The np.reddit.com
domain is read-only, and displays a note to that effect at the top of every comment thread.
It doesn't literally prevent brigading. Redditors could manually delete the np. prefix and vote anyway. But they probably won't, for the most part.