• by Laurie Sullivan  @lauriesullivan, February 25, 2011

Google laid out details of how the search engine will filter results through an algorithmic improvement to its ranking, a change that impacts about 11.8% of its queries. 

Google Fellow Amit Singhal and principal engineer Matt Cutts explain that the update should reduce rankings for low-quality sites that add little value for users of its search engine or content from other Web sites. This move is intended to provide better rankings for high-quality sites that post original content and information, such as research, in-depth reports and analysis.

Singhal and Cutts explain in a blog post that Google's engineers can't make a major improvement without affecting rankings for many sites. The changes did not solely rely on feedback from the "personal blocklist Chrome extension" launched earlier in February. When making the decision, Google engineers did compare the data gathered through the browser tool to identify specific sites. "If you take the top several dozen or so most-blocked domains from the Chrome extension, then this algorithmic change addresses 84% of them, which is strong independent confirmation of the user benefits," they wrote.

The change initially rolls out in the U.S. to improve Google Search. Other countries will follow as feedback comes in. The search engine has been under fire to improve search results for each query. Some believe company executives have gone on a witchhunt to correct and punish companies -- jcpenney.com and overstock.com -- trying to game the algorithms by exploiting backlinks.

Demand Media, which has been under fire for scraping and repurposing content, responded to Google's post. Larry Fitzgibbon, Demand Media's executive vice president of media and operations, acknowledged the change and how it could influence rankings for content on the Web site. The company, which recently issued an IPO, has not seen an impact on its content and media business, which some view as a "content mill" or "content farm."

Fitzgibbon wrote that the changes were discussed during the company's 4Q earnings call in which it posted $1 million in profit, up from a net $3.9 million loss in the year-ago quarter.

Demand Media took spot No. 13 in comScore's top 50 U.S. Web properties for January 2011, with 75.5 million unique visitors. The ranking is based on data from the comScore Media Metrix service.