I recently read an article in The Register by a friend of mine, Matt Asay. He has a pretty good point about Android being the dominant player in the BRIC market. I can remember going to CES and being surprised ten years ago how many odd cheap devices were using Linux, but had really terrible interfaces. Thanks to Android, now those devices have a compelling interface and access to the Android application market.
Matt's point though is about revenue. If you can't charge people for apps because you don't have a credit card on file, and advertising isn't targeting them necessarily, how do application developers make money in those emerging markets?
For that matter, what about devices without a UI at all? Is there a way to monetize services without an interface? If you have a smart phone that can connect to a headless device in your home where the headless device is doing some "work" for you, like keeping track of energy usage for example, would the money be made on the secondary device and the application on the smartphone is just a way to connect to it to get at the information?
There are certainly many questions left to answer on this topic. It will be really interesting to see where the market goes, especially in the BRIC countries.