Don Kellogg over at Nielsen Mobile has been cranking out some very interesting research about how we use our mobile devices. His latest work shows that Android users spend more time using their apps than they do using their browsers. The ratio is around 67% of time spent on apps, with 33% spent on browser, during an average Android user's 56 minutes spent per day using the Internet via their smart phone.

That means Android users are interacting with Facebook via the Facebook application, and not the Android browser. That's not exactly surprising, of course, but what is surprising is just how much the top 10 Android applications dominate users' attentions. According to Nielsen's numbers, the top 10 applications in the Android marketplace account for 43% of all application usage on the Android. Add to that the remaining top 40 apps, and overall the top 5o applications in the Android store account for over 60% of all application usage on the phone.

What does this mean for developers? It means the Android app store is a dangerous place to take your business. With over 250,000+ applications available, it would certainly appear than only a very small portion of those apps are actually being used by the public at large. As a business model, targeting Android alone might not be the best option, right now. It'll be interesting to se how these numbers change over time. Of course, this also means that if you are the creators of one of those top 50 applications, you're in a terrific position to monetize your application, whether through advertising or through selling the app outright.