Fantasy football is an armature competition in which users compete against each other as league general managers of virtual teams built from real professional American football players in the National Football League. The strategies of winning is similar to that of the real football competitions in that the users must manage drafting, trading, adding or dropping players, and changing rosters. The growth of the Internet has significantly increased the popularity of fantasy football, particularly because Fantasy football providers such as ESPN, Yahoo, CBS, and the NFL itself are able to keep track of statistics entirely online, eliminating the need to check box scores and newspapers regularly to keep track of players. Most leagues have a single week championship in Week 16 of the NFL season.