Also, I'm going to argue just against my experience with urban teens living in more diverse communities which doesn't really align with this kids experience.
So right away, if you want a successful smartphone app in the U.S. then you need to target, urban white men between 18-29 with at least some college and 75000+ a year in income.
I think as you say more people should target international etc... but people build toward the problems they have and the language they know. Whatsapp is killing it because they broke out of the mold. So yes, they should for many reasons, but if you just follow the money then who you target looks very homogenous.
[1] http://www.pewinternet.org/fact-sheets/mobile-technology-fac...
[2] http://www.voxburner.com/publications/6766-who-makes-in-app-...
A successful smart phone app based on these metrics is the one with the largest user base. You get that user base by providing a simple to use product that quickly addresses a need for the largest number of people, rich, poor, white, black, etc...
Now, if you're talking about targeted applications like certain types of gaming apps. Or apps that provide an extended retail experience? This is when you talk about focused demographics.
Totally agree here.
A successful smart phone app based on these metrics is the one with the largest user base.
This is where we diverge. An app is only as successful as what it can make money from. Having a billion people use something and they don't generate revenue from it is worthless in the long run - bloated investments not withstanding.
A reliable proven to be profitable user base is what consistently makes money - the facebooks etc... are extreme outliers that got lucky with monetization after growing the userbase are not really cases to be emulated.
Granted there are other cases of revenue models that we may not even be aware of that are in play. For instance Twitter initially was making money off SMS bulk transactions. They would buy SMS network blocks in volume and sale broadcasting blocks to marketers at a markup which was lower than outbound texting rates. There was good money in the margins here for a time. They don't like to talk about it publicly but they still admit that the service was built around a focus on SMS... https://blog.twitter.com/2010/introducing-fast-follow-and-ot...
This is why for a while they also tried like hell to push people to take Tweets over SMS instead of having pulling them from the web via a web browser or other web based client. Smartphones unexpectedly gimped this business model for them.
There are boutique companies today that still are trying to eep out business around this model such as this one... http://www.fabit.com/products/mobile/sms/websms/overview.asp...
...now I'm just rambling...