Up/down is sufficient to capture the vote itself but there is more data in there to consider, like: 1. How long did it take for the person to vote in the first

Up/down is sufficient to capture the vote itself but there is more data in there to consider, like: 1. How long did it take for the person to vote in the first place? (Might change weight; if we're talking cars, nobody really knows if they "like" it 4 minutes after purchasing and it means something different if the rating appears 3 months later.) 2. Has the vote changed between up/down? Has this happened twice? 3. Has the person voted for other things in similar categories? Might make sense for phones, over a period of years. Doesn't make sense for a person to buy and rate 20 different chairs in a week. Use it to give credibility.