When I started writing NodeDroid, I did it to learn about writing mobile applications, and all of its associated technologies. One of those technologies was advertising. I added Admob advertising to the bottom of the application, and wated for the megabucks to roll in :). In the little over 3 months that its been available, it has netted a grand total of $13.88US. Thats enough to cover hosting costs, but thats about it.