Google Patent: Methods and apparatus for ranking documents

This Google patent describes a method and a device that can be used to classify and rank documents on the Internet. The invention focuses on recognizing and ranking sources and documents in different categories to find relevant information on a particular topic. A central element is the formation of topic clusters, which group together documents with similar content and are characterized by a focus. The sources are evaluated according to their credibility and expertise in relation to a specific topic and stored in a database that is used to evaluate the relevance of the documents.