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.

According to Matt McGhee at Search Engine Land,

there are two primary ways Google will measure page speed:

1. How a page responds to Googlebot
2. Load time as measured by the Google Toolbar

You can check on your site speed in Google’s Webmaster Tools, under Labs > Site performance, and Google points to several other resources to work on your site speed:

• Page Speed, an open source Firefox/Firebug add-on that evaluates the performance of web pages and gives suggestions for improvement.
• YSlow, a free tool from Yahoo! that suggests ways to improve website speed.
• WebPagetest shows a waterfall view of your pages’ load performance plus an optimization checklist.
• Many other tools on code.google.com/speed.

Google emphasizes that page speed won’t trump actual relevance.

What do you think? Is this a good move for ranking?