Amazon's (NASDAQ:AMZN) recently announced mobile advertising network takes direct aim at Google (NASDAQ:GOOGL) Android's adverting dollars. Mobile advertising remains a huge growth area as the majority of the world's next 2 billion Internet users will experience the Internet for the first time on a mobile device. In this video, Motley Fool contributor Steve Heller explains what sets Amazon's mobile advertising business apart from Google's, and why Google should keep a watchful eye on Amazon. As for the current state of mobile advertising, an unlikely leader has emerged ahead of Google.