Google is building Android not so they can make great mobile devices and sell them to consumers. Rather, they are making them for these two simple reasons: (1) to disrupt Apple’s growing dominance of mobile devices, both so Google doesn’t have to rely on Apple for access to their users and to eliminate their paid-for application model; and (2) so Google can control the mobile industry and thus secure advertising from it.

This helps explain some puzzling moves by Google. For example, Android’s market may not be terrible in comparison to Apple’s App Store for paid applications just because Google hasn’t yet finished it; rather, discouraging paid applications on the Android platform is in Google’s interest. If users won’t pay for applications, what will developers use to make money from their applications? Advertising. And Google conveniently owns one of the largest mobile advertising providers, Admob.

Interesting analysis on Google's motives in the mobile space.