BusinessWeek publish Apple vs. Google, an article on Apple Inc. and Google subtitled "How the battle between Silicon Valley's superstars will shape the future of mobile computing". This article gives clues to understand what is going on between the two compagnies that were strategic allies and that now consider each other more likely as a concurrent. It seems to be all a matter of how to make money from ads on mobile devices.
The side bar contains the following table :
Here is another article, The battle for the clouds (Google) from the What matters..... blog to complete the BusinessWeek article.