Mobile gaming is just one of the many ways that smartphones are taking over as our primary computing device. Engadget reports on data from Flurry analytics that shows iOS and Android devices increasing their share of the money spent on portable games.
In 2009 iPhone (iOS) games accounted for 19% of the total money spent on portable games, with portable game devices like the Nintendo DS accounting for the remainder. In 2010 the combination of iOS and Android accounted for 34% of the revenues on portable games. Numbers like this explain why Apple heavily advertises the gaming capabilities of the iPhone and iPod Touch. I expect that Windows Phone 7 will contribute to the 2011 numbers as one area where it really excels is in gaming with Xbox Live.
If you are curious, smartphones also account for a noticable share of the total video gaming market, with iOS and Android games accounting for 8% of the revenues for video game software. Video consoles account for 76% of the revenues, but as smartphones are able to run more sophisticated games, and more people use them as their primary computing device, I expect to see their share of the total gaming market to grow significantly.