Social gaming

According to Wiki, Gamification is the concept of applying game-design thinking to non-game applications to make them more fun and engaging. It has proven to be very successful in attracting large numbers of users. Taking age old games and adapting them to the net with extra social sharing features built in have helped King the makers of Candy crush build large audiences and earn up to $1 million per day. Beyond games, Gamification can apply to education (Khan Academy), pricing models (Uber), and Loyalty plans (Aeroplan).  It doesn’t stop there; corporates are using Gamification to create a sense of competition within organizations. For example, concepts such as leaderboard status can be applied to marketing individuals who are trying to get the most followers or to sales teams who are trying to sell the most volume.

Social network-based gaming has exploded in recent years, facilitated by Facebook. Social gaming is increasingly becoming a key focal point within the gaming community due in large part to the higher average revenue per unit through monetization of global social networks, local social networks, mobile social networks, and second screen social gaming.

For more examples refer to: http://www.gamification.co/

A bunch of stats are available here: http://www.go-gulf.com/blog/social-gaming-industry/