Google lands Web search patent

By Stefanie Olsen, Staff Writer
CNET

February 26, 2003

Google this week was granted its first patent by the United States Patent Office for a method of determining the relevance of Web pages in relation to search queries.

The patent, which Google filed on Jan. 30, 2001, and was granted Tuesday, governs methodology for parsing through Web documents to deliver Web surfers the most relevant pages for their queries.

Specifically, it deals with "an improved search engine that refines a document's relevance score based on interconnectivity of the document within a set of relevant documents," according to a summary of the patent.

The invention could affect search companies that are building technology to intelligently rank Web pages in relation to search queries. In the last year, Web search has become one of the hottest markets on the Internet. Many companies are furiously developing advanced tools and techniques that will index the Web more effectively and so, they hope, draw visitors.

As the top destination site for online searches, Google fields more than 150 million worldwide queries every day. When a visitor types a keyword into the search field, its Web servers send the request to an index server, which identifies Web pages containing words that match the query. Document servers with the matching pages deliver links to the visitor in less than half a second, according to Google's site.

The new patent deals with the process for finding matching documents. Under the methodology, Google turns up an initial set of documents related to the keyword and then ranks each page with a "relevance score." Next, it calculates a "local score value" that quantifies "an amount that the documents are referenced by other documents in the generated set of documents," according to the filing. Finally, the local score values influence the relevance ranking of a page.

According to the patent, "a search engine modifies the relevance rankings for a set of documents based on the interconnectivity of the documents in the set. A document with a high interconnectivity with other documents in the initial set of relevant documents indicates that the document has 'support' in the set, and the document's new ranking will increase. In this manner, the search engine re-ranks the initial set of ranked documents to thereby refine the initial rankings."

The invention's assignee is Mountain View, Calif.-based Google, and its inventor is Krishna Bharat, a senior research scientist at the company. He holds a doctorate in computer science from Georgia Institute of Technology.

Google would not comment on the patent.

The company now has three outstanding patent applications. Two concern methods and technology for providing search results in response to an ambiguous search query. The third deals with methodology and technology for delivering search results that use analysis of Web page usage.

In addition, Google co-founder Larry Page invented a methodology called PageRank, which was patented to the board of trustees of the Leland Stanford Junior University on September 2001. PageRank is one of Google's recipes for calculating the popularity and relevance of Web pages based on the number of other pages linking to it.