Official Google Blog: Introduction to Google Search Quality

Official Google Blog: Introduction to Google Search Quality: "Search Quality is the name of the team responsible for the ranking of Google search results. Our job is clear: A few hundreds of millions of times a day people will ask Google questions, and within a fraction of a second Google needs to decide which among the billions of pages on the web to show them -- and in what order. Lately, we have been doing other things as well. But more on that later."