Google Inc.

for the Web Hyperlink analysis algorithms allow search engines to deliver focused results to user queries.This article surveys ranking algorithms used to retrieve information on the Web. Information retrieval is a computerscience subfield whose goal is to findall documents relevant to a user query in a given collection of documents. As such, information retrieval should really be called document retrieval. Before the advent of the Web, IR systems were typi-cally installed in libraries for use mostly by reference librarians. The retrieval algo-rithm for these systems was usually based exclusively on analysis of the words in the document. The Web changed all this. Now eac