Introducing our new guide to Google Search ranking systems

Over the years, through blog posts and other public communications, Google has regularly shared
information about our automated ranking systems and how they operate. Now we’ve created a centralized
page called “A guide to Google Search ranking systems” to make it easier for creators and others
to learn about our more notable systems. This new page will also help us as we communicate how
our systems work and when we update those systems.
Source: Google Webmaster Central Blog
Link: Introducing our new guide to Google Search ranking systems