Official Google Blog: Technologies behind Google ranking: "Technologies behind Google ranking
7/16/2008 10:53:00 AM
In my previous post, I introduced the philosophies behind Google ranking. As part of our effort to discuss search quality, I want to tell you more about the technologies behind our ranking. The core technology in our ranking system comes from the academic field of Information Retrieval (IR). The IR community has studied search for almost 50 years. It uses statistical signals of word salience, like word frequency, to rank pages. (See 'Modern Information Retrieval: A Brief Overview' for a quick overview of IR technology.) IR gave us a solid foundation, and we have built a tremendous system on top using links, page structure, and many other such innovations."