The Anatomy of a Large-Scale Hypertextual Web Search Engine
Sergey Brin, Lawrence Page · 1998
"Ranking web pages by the link structure of the web itself (PageRank) produces dramatically better search than keyword matching."
Search engines before Google mostly ranked pages by matching keywords — how many times did the search term appear on the page. That approach was easy to game (stuff a page with the word 'concert tickets' a thousand times) and didn't capture which pages people actually trusted. Brin and Page's insight: treat every hyperlink on the web as a vote of confidence from one page to another. A page gets a higher rank not just from having many links pointing to it, but from being linked to by other pages that are themselves highly ranked — importance flows through the link graph, recursively.
Read more about the topic
Information Management: A Proposal
"A linked hypertext system over a network would let information at CERN (and everywhere) be shared without central control."