Google "Moonshots"

the Mountain View, California-based company has been involved with 127 deals in the past three years, more than double the number from January 2008 to 2011…

Google’s strategy is in contrast to that of Apple Inc., the only Silicon Valley company with more cash on its balance sheet. The iPhone maker has only taken part in 12 deals in the past three years, according to data compiled by Bloomberg, and has been sending cash back to shareholders in the form of dividends and buybacks. Google’s shares have climbed 97 percent over the period, while Apple has advanced 48 percent.

Bloomberg

One possible explanation?

…Google has a notoriously terrible share structure in which the founders have high-vote Class B shares and everyone else has low-vote Class A, which will soon be partially replaced with extra-insulting no-vote Class C shares. In this, Google is like Facebook and lots of other recently public companies that have chosen to avoid good-governance pressure (return capital! listen to shareholders!) by just starting out with terrible governance. If your shareholders can't (effectively) vote, then there's no sense in them submitting nonbinding shareholder proposals demanding that you maximize shareholder value. You're left pretty much in peace, and you can do classically shareholder-unfriendly, empire-building things like being acquisitive rather than classically shareholder-friendly, management-disciplining things like returning cash to shareholders.

Bloomberg

I'm sure share structure does play a role here, but I still prefer Jean-Louis Gassée's explanation of “Apple buys technology” to improve its current and future products and their relevant ecosystems while Google “rolls the dice” in search of the next big thing.