13of40 was talking about a single button that mass downvotes multiple comments. None of the default (nor popular) clients support this functionality, but you could script your own version using the reddit API.
I was talking about a button that sets the score for a single submission to zero and makes it stick. I know the numbers are fuzzed, but I don't think fuzzing will take something with a score of 1 and show it as 0.
