Last December, Google publicly announced a new ranking factor: site speed. Today, Google announces that site speed has joined the 200+ other ranking factors in their algorithm.
However, not all sites will be affected. In the blog post, Amit Singhal, Google Fellow, and Matt Cutts, Principal Engineer, Google Search Quality Team (you’ve heard of them?), say that the change has actually been in place for “several weeks,” and isn’t even that widespread:
Currently, fewer than 1% of search queries are affected by the site speed signal in our implementation and the signal for site speed only applies for visitors searching in English on Google.com at this point. We launched this change a few weeks back after rigorous testing. If you haven’t seen much change to your site rankings, then this site speed change possibly did not impact your site.