Not all of the developers on the App Store are starting up gigantic companies or breaking new indie ground. A large number of them, like Darren Sillett and his wife Samantha of Mighty Mighty Good Games, are just experienced programmers who choose an idea and stick with it, iterating and testing to see what works and what doesn't on the App Store. Sillett's biggest app is one of a few versions of Sudoku on the iPhone, but since day one, he and his wife (former Microsoft developers -- Sillett actually worked on Windows Vista) have been playing with this idea of word games on the iPhone, and they've tested all of the tricks. They've released free versions, included ads, tried different pricing and versions, and so on. As a result, they've found success with over ten million downloads of their free apps and over 200k in paid-app sales.
Sillett told me that his next big step will be to bring some of his apps to the iPad, and he's planning on going universal. While there will be some extra stuff in the iPad version, he thinks that universal is the best choice for his customers, at least while he's testing the waters. We also talked at length about iAds; Sillett says that ads have proven more beneficial for him in just the last few months, as ad companies and customers have really started to move the market along.