Another factor for big wins is that some progressive slots are connected between a lot of casinos, so tons of players are adding to the jackpot. Also, when someone does win the jackpot, the number does not reset to 0 - it restarts from a predetermined amount, usually 1 million. The winnings are huge because the longer it takes for someone to win, the bigger the amount gets.
Whenever a player spins the reels, a percentage of their bet goes towards the jackpot pool. In progressive slots games, multiple players contribute to the jackpot for a selected game.
Progressive jackpots are a favorite among real money slots players because of the potential for big wins. Top Progressive Jackpot Slots and How They Work
