Several crowdsourcing competitions were held in recent years.
Red Balloons challenged participants to find 10 red weather balloons moored at secret locations throughout the US.The winning team found all balloons within 9 hours using an incentive scheme that encouraged not only reporting the balloons, but also recruiting new participants.
The Tag Challenge was similar to the Red Balloons challenge, but the search was for 5 individuals moving around 5 cities based on their picture and t-shirt. A similar incentive scheme worked.
The MyHeartMap Challenge crowdsourced creating a map of AEDs throughout Philadelphia. Crowdsourcing did not produce the expected result here. It did work in the Netherlands, however. Cultural differences? Monetary incentives “crowding out” altruistic spirit? Not enough media support?