The five biggest companies that Google has gobbled

Google has wrapped its tentacles around yet another aspect of digital life, announcing plans earlier this year to buy smart-phone giant Motorola Mobility. The 13-year-old search-engine company has a history of staying ahead through smart acquisitions. Here are its five largest:

1. Motorola Mobility ($12.5 billion)
2. DoubleClick ($3.1 billion)
3. YouTube ($1.65 billion)
4. AdMob ($750 million)
5. ITA ($700 million)