Foursquare tip voting
The introduction of tip voting allowed any Foursquare user to upvote or downvote a tip (also known on other websites as a “review”) to indicate whether or not it was helpful. Before tip voting, you were able to “like” a tip, but over time, we’d heard a lot of feedback that people also wanted to be able to “dislike” a tip as well.
The end result shown below also included changing up the tip hierarchy to prioritize some of the elements we thought were most important for a tip. Additionally, one of the visual design goals was to provide equal weight to both the positive and negative (upvote and downvote) action buttons.