Some sites will go up and some will go down because of the new algorithm of Google.

Sites which are low-value add for users or copy content from other websites or sites that are just not very useful will go down. It will provide better rankings for sites with original content such as research, in-depth reports, thoughtful analysis.

Google says they have a responsibility to encourage a healthy web ecosystem.

Our goal is simple: to give people the most relevant answers to their queries as quickly as possible. This requires constant tuning of our algorithms, as new content - both good and bad - comes online all the time, The Official Google Blog said.

For the beginning Google is launching this change in the U.S. only.