The booming mobile and free-to-play video game markets are seriously weighing down today's disk-based game sales. Sales of new and used video game disks made up just 35% of overall video game sales last year, according to research firm Newzoo. That's down from 40% in 2012.
Meanwhile, smartphone and tablet games are taking control of the video game industry. For example, King's popular Candy Crush Saga game earns over $1 million per day from in-game sales of extra lives and power boosters. Mobile consumers play King's games more than 1 billion times a day --up three-fold from a year ago. The company announced its plans to go public on Tuesday.