When Google chief executive Eric Schmidt took the stage at Mobile World Congress, it seemed that many of his remarks were meant to placate the mobile phone industry. And for good reason: Over the last year, Google has become a mobile powerhouse -- this was Schmidt's first keynote in Barcelona, after all - that, in many ways, competes with wireless service providers. The past year has seen a proliferation of Android phones and the debut of powerful mobile apps such as Google Voice and Maps Navigation. It's a good thing in that Google's driving sales, but it's also a cause for concern. Here are five reasons mobile telcos should be worried about Google: