Here's an excerpt from the "Letter from the founders":
Our business environment changes rapidly and needs long term investment. We will not hesitate to place major bets on promising new opportunities.There's a lot of good stuff to read in here.
We will not shy away from high-risk, high-reward projects because of short term earnings pressure. Some of our past bets have gone extraordinarily well, and others have not. Because we recognize the pursuit of such projects as the key to our long term success, we will continue to seek them out. For example, we would fund projects that have a 10% chance of earning a billion dollars over the long term. Do not be surprised if we place smaller bets in areas that seem very speculative or even strange. As the ratio of reward to risk increases, we will accept projects further outside our normal areas, especially when the initial investment is small.
We encourage our employees, in addition to their regular projects, to spend 20% of their time working on what they think will most benefit Google. This empowers them to be more creative and innovative. Many of our significant advances have happened in this manner. For example, AdSense for content and Google News were both prototyped in “20% time.” Most risky projects fizzle, often teaching us something. Others succeed and become attractive businesses.