Many corporations and organizations love to build web apps as they can easily and quickly scale the whole planet. There's three things to think about, both current population, internet adoption, and potential for revenue.
For the current population, you can see from this map above that most of the world's population is in Asia.
For Internet Adoption you can check out these stats on who's using the web, and subsequent growth rates.
Lastly, during Bay Chi Web this week, Kelly Goto discussed that China's youth has only 9 dollars in currency to spend online a year, which is vastly different than the hundreds or thousands North American youths spend.
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