Over the last decade, people's behavior during their daily train ride has completely changed. In the past, Japanese were known to be avid readers of paperbacks (bunko) and manga magazines, and would do so even on Tokyo's notoriously crowded trains. Now, however, it is rare to spot someone on the train who is not staring into their cellphone.

A large amount of them are playing social games. And companies like Gree and Mobage, which produce social games, are earning more than traditional video-games titans such as Nintendo and Sony. But these huge sales are actually supported by just a small percentage of players.

Parents being shocked to find their children spending ridiculous amounts of money on cellphone games is old news — and certainly such cases are often reported to the National Consumer Affairs Center, with more than 20 percent of their annual 5,000 inquires related to teenager-related cellphone spending. However, the other 80 percent of the complaints are by adults, particularly those in their 30s, who plead that they have felt cheated into spending large amounts on virtual game items. It is definitely adults, rather than kids, who have propelled the social-game market to the point where it has surpassed the home videogame market for first time in 2012.