Prediction markets allow people to bet on future events like president election or celebrity marriage. Basically, you can bet on all types of events. A prediction market can provide a unique data about people’s opinions and these can determine a probability of a result. Prediction markets were always centralized with central decision power.
Everything changes the blockchain technology and smart contracts, which make it possible to run a prediction market in a completely decentralized way and without any central power authority. Also, you can make money by betting on events. Currently, there are in development two projects – Augur and Gnosis, where the aim is to create a decentralized prediction market based on the blockchain technology.