The trick to monetisation is not focusing on monetization, argues Supercell boss Ilkka Paananen.
The Clash of Clans and Hey Day developer has been raking in the cash since it launched the two iOS games last summer.
"The huge irony here is that if the monetisation is not your number one priority, that actually leads to better monetisation," said Paananen.
"When you prioritise engagement and retention - making a great game that people play often and want to play for a long time - they are happy to pay. We want to design games that people can theoretically play for years."
The lesson, suggested Paananen, is that metrics without art doesn't mean fun, and monetisation depends on players having a good time.
"There was a time, especially in the social games industry, where people thought you could create great games based on a spreadsheet: that creativity and design wouldn't really matter, because it was all about some maths," he explained.
"Games are still a form of art, not a form of science. You can't design fun on a spreadsheet. And if you want to make an industry for the long-term, if you can't create fun games, there's no future."
Of course, Supercell owes a great deal of its success to the nature of the platform it targets; iOS offers developers a chance to take advantage of a truly global platform.
"Our growth speaks a lot about the platform that we're on, and how quickly games can spread organically," said Paananen.
"It's also been exciting for me personally to see how global this business has become: we've been at the top spots in Western countries, but also number two in China, and in the top five in Japan. That's really exciting."