Whomever does it needs to take into account the fact that up and down is stupid. Slashdot always had a nice system, when you had votes to give, and you did not always have them, you would qualify those votes. Interesting, Informative, New, On-Topic for positive upvoting versus Boring, Inaccurate, Repost, and Off-Topic. Slashdot's idea of having a person's votes actually a limited resource that do not pop up constantly was a boon to their use. They meant more and there was a regular, random, event that let people double check on other people's votes, people whose votes regularly were found to be countered by review would have less chance of the job and excess abuse would find them losing the points to vote with and the ability to review. When there is only a binary response to content people use it for like and dislike, with a gradient option that has nuance people think a little more about their use.