Google buying Motorola Mobility is a massive acquisition in the tech world. There's some fantastic analysis on the news, but this paragraph by Jon Gruber captures it all nicely:
Google just spent almost two years of its profits to buy a second-rate phone maker that itself is unprofitable,1 almost went bankrupt, and is arguably only the third-best maker of Android devices, behind HTC and Samsung.
It's going to take a lot of ads to claw that purchase back, but it will likely be worth it to stave off a potentially humiliating, patent-based destruction of Android.
Also a great question raised today: What is it again that Google do; software, hardware, sales...?
Who knows. They do still make a ton of money, though, this purchase will be funded out of the $35 billion sitting in Google's cash account.