The most used search-engine in the world is here with an update to the way it displays search results. It will now also take into account a site’s speed/performance when ranking it, apart from the myriad other parameters it employs.
While Google is giving site owners a headstart by not incorporating the new feature wholesale into all its servers (it applies only to visitors searching in English on Google.com and will affect only 1% of all search queries), it is also urging them to improve their site speed, so as to improve their customers’ user experience as well as their site’s overall page rankings. Google also stresses on the fact that “improving site speed also reduces operating costs.”
To aid site owners, webmasters, and web authors in this process, Google has also provided a whole set of tools (most are third party) that can be used, and they can be found here.
Also refer to Webmaster Tools, which "shows the speed of your website as experienced by users around the world".
For more information about this, read Google’s official blog.