This is the third notable move against irrelevant content this year, following two similar changes implemented in 2010. In January, Google adjusted its relevancy algorithm to reduce the presence of Web spam and low-quality content following a series of articles and blog posts about how Google search results had become increasingly polluted with junk.
Earlier this month, Google released a Chrome browser extension, Personal Blocklist, which allows users to block domains they deem to be irrelevant and provides this information back to the company. Google said that it intends to consider user-generated blocklist data as a possible signal when determining site relevance.
Google's latest adjustment has been dramatic, affecting 11.8% of the Web sites appearing in Google search results in the U.S. The company plans to implement these changes in other locales over time.
"This update is designed to reduce rankings for low-quality sites -- sites which are low-value add for users, copy content from other Web sites or sites that are just not very useful," said Google fellow Amit Singhal and Google principal engineer Matt Cutts in a blog post.
Cutts and Singhal note that while the search algorithm adjustment didn't utilize data gathered through the Personal Blocklist extension, they were pleased to find a strong correlation between sites affected by the change and sites blocked by users. Among the top dozen or so most blocked sites, the algorithm change affected 84% of them.
Curiously, Google now appears to be avoiding the term "content farms," which it previously defined as "sites with shallow or low-quality content." Might this have something to do with a desire to avoid litigation from aggrieved producers of junk content? Declining to address the legal ramifications, a Google spokesperson explained, "That term means different things to different people, so we've tried to be more descriptive, referring to high- and low-quality sites instead."
Coincidentally, Demand Media, a company that has been pointed to as an example of a content farm, on Thursday published a blog post noting that it applauds Google's changes and that the search algorithm adjustments have not affected its business.
"It’s impossible to speculate how these or any changes made by Google impact any online business in the long term -- but at this point in time, we haven’t seen a material net impact on our content & media business," wrote Larry Fitzgibbon, EVP of media and operations for Demand Media.
That was at 10:34 pm PST, when the U.S. stock market was closed.
On Friday, in the wake of Google's relevancy changes, Demand Media's shares opened down about 4% but had largely recovered later in the day. Either investors aren't really all that worried about Google's effort to bury low-quality content or they don't believe that the content produced by Demand Media falls into that category.
Demand Media went public last month with a market capitalization of $1.9 billion, which suggests at least some confidence in the company's business model.