On 9 April 2010, Google added site speed to their search ranking algorithms.  Site speed reflects how quickly a website responds to web requests.

Google will measure page speed in terms of how a page responds to Googlebot, and the load time as measured by the Google Toolbar.

Site speed is one of about 200 different ranking factors in Google’s algorithm, and other factors such as quality and relevance are equally important in determining a site’s Google ranking.

Google’s Amit Singhal says “the focus remains on improving the user experience on Google.com, and the company can’t do that if it gets the relevance of search results wrong. We want to return faster sites but not at the expense of relevance.”  Read more on searchengineland.com

Click here for a list of free tools that you can use to evaluate the speed of your site on the Google Webmaster Central Blog.