Making money was probably not the primary object behind Android. When Google released the mobile OS in October 2008, the idea was simply to bring openness of the Internet to the mobile platform. Google was already making billions then, so its focus was more to come up with a robust mobile OS, that would be open source, free to license, and easy to develop apps for. Needless to mention, their plans worked well…very well.
Now, Google claims that the company has started making money based on the ads that are displayed in the mobile apps. In fact, the revenues may even hit $10 billion a year if “Google could get just $10 from each user per year”. To make this happen the platform has to reach at least 1 billion users world wide, which realistically is a long road ahead. However, it is possible given Android’s astronomical growth in the last 2 years.