Yahoo Fantasy is an online platform that allows users to create and manage their own fantasy sports teams. Participants can join leagues for various sports, including football, basketball, and baseball, where they draft real-life athletes to compete based on their actual performance in games. The platform offers features like live scoring, player statistics, and customizable league settings. Users can engage in trades, make roster changes, and participate in weekly matchups, making it a popular choice for sports enthusiasts looking to enhance their viewing experience through friendly competition.