In a Google Blog posting this week, the search giant has announced a major change to its search algorithms in the United States which the company says will affect about one out of every nine queries.

Google says the change, which has been in the works for several months, is designed to reduce the rankings of low-quality sites which simply copy content from other websites or are simply not that useful while increasing the rankings for higher quality sites which feature original information and content.

In the post, Google Fellow Amit Singhal and Principle Engineer Matt Cutts, explain the changes to the search algorithms happen quite regularly but are typically so subtle that searchers seldom even notice the difference.

Because this week's changes will affect a significant percentage of searches , the company decided to notify the blogosphere that changes were afoot. Singhal and Cutts says that Google's goal remains the same, to give people the most relevant answers to their queries as quickly as possible.

"Google depends on the high-quality content created by wonderful websites around the world, and we do have a responsibility to encourage a healthy web ecosystem. Therefore, it is important for high-quality sites to be rewarded, and that’s exactly what this change does." wrote Singhal and Cutts.

Canadians won't see any changes in the near term as the changes have only been implemented in the U.S. Google says it roll the changes out elsewhere over time.

Discuss Google's changes in Digital Home's World Wide Web forum .