Gamification campaigns work because they bring fun into marketing. Consumers see brands differently when they can connect through games. Marketers love games because they can create campaigns on a fixed budget, knowing exactly the cost of redemption at the end of the program. Games can be effective at every step of the customer journey. Sweepstakes are an excellent tactic to drive awareness at the top of the funnel, while instant-win rewards do very well to drive advocacy at the bottom of the funnel.
Today, games can be delivered digitally or via traditional off-line methods, such as game pieces attached to retail products. No matter the tactic, the same legal rules (which can vary state by state) apply. You cannot require purchase for sweepstakes or games (games of chance where winners are randomly selected), but you can in contests, where every entry is judged to determine the winner.