What is a Badge?
A badge is a congrats!
A virtual pat-on-the-back for taking an action or for doing something correctly.
These prizes have no dollar value but offer "bragging rights" to the winner as well as an intrinsic sense of accomplishment. They can be awarded for accomplishing pre-determined milestones in a Challenge, such as answering the first question correctly, or playing all questions in a Challenge.
These achievement badges typically appeal to gamers and to people who particularly enjoy being merited for their efforts.