Google has filed several patents for technology that seeks to determine the veracity of the content offered up in search results, including news aggregated by Google News, The Guardian reports. Patent WO 2005/029368 is for technology that ranks news according to accuracy, reliability and topicality. Google wants to develop algorithms that account for the amount of important coverage produced by a source, the amount of traffic it attracts, circulation statistics, staff size, breadth of coverage and number of global operations.

A Google spokesperson said the company did not discuss individual patents but that Google News is "evolving all the time." Google News emerged directly from the company's policy of allowing its staff to spend a fifth of their time on their own projects. It now links to 4,500 sources worldwide and has become a valuable driver of traffic for traditional media sites and thousands of smaller, online publishers.

Competitors Microsoft, Yahoo and Ask Jeeves are also spending huge sums to develop new versions of the complex algorithms that power search engines. The search engine market is in a period of huge development and change, according to Forrester technology analyst Charlene Li: "As MSN launches its new search engine and players like Yahoo, Ask Jeeves, A9 and a slew of startups continue to innovate…the market remains open to big shifts."