Google published on their blog: "This update is designed to reduce rankings for low-quality sites—sites which are low-value add for users, copy content from other websites or sites that are just not very useful. At the same time, it will provide better rankings for high-quality sites—sites with original content and information such as research, in-depth reports, thoughtful analysis and so on."
High quality content is becoming more important for SEO"These are sites that people want to go down, and they match our intuition," Matt Cutts is quoted as saying. It'll be likely that content is going to be affected on a page-by-page (or article-by-article) basis, as opposed to an entire domain being affected. Companies need to adapt again their SEO strategy and enhance the quality of their pages.
Eworks WSI encourages Google's actions on content farms.
This is encouraging for web publishers who pay highly trained professionals to produce quality content and for those who search on Google.