World of Warcraft

http://www.youtube.com/watch?v=pevKSVo5X40 http://www.youtube.com/watch?v=OhJcqE5sx5I http://www.youtube.com/watch?v=xt5N6pJB77w http://www.youtube.com/watch?v=-sUkd8zbpdI

At some point, Blizzard discovered the magic formula to keeping game subscriptions active, instead of focusing on player driven content and character progression for its own sake – get players hooked on the endless treadmill of gear score upgrading.