Data is absolutely vital to Google's success; without data, Google is pretty much useless when it comes to search. Hal Varian explains on the official Google blog:
Over the years, Google has continued to invest in making search better. Our information retrieval experts have added more than 200 additional signals to the algorithms that determine the relevance of websites to a user's query.
So where did those other 200 signals come from? What's the next stage of search, and what do we need to do to find even more relevant information online?
What an interesting question. I wonder what the answer is. Oh, here it is:
Storing and analyzing logs of user searches is how Google's algorithm learns to give you more useful results. Just as data availability has driven progress of search in the past, the data in our search logs will certainly be a critical component of future breakthroughs.
Cashing In On Data
That's right. Without data, who knows where search could be now. AOL might still be prosperous. There's also this funny bit about how Larry and Sergey initially tried to license their algorithm to new, already existing search engines, but no one bit, and so they made their own. You gotta respect the data!
For more on the importance of data, you might also be interested in the ever-going series on FlowingData on why data matters.