A progressive jackpot is a jackpot which increases each time the game is played but the jackpot Many slot machines and video poker machines feature a progressive jackpot. The jackpot increases by a small predetermined amount each. Learn everything you needed to know about progressive slots here. Includes the biggest jackpots, how to win, your odds and more. Online progressive slots are the most exciting kind of online slot machines. The jackpots get bigger all the time - they could make you an instant.