Google is continuously finding new ways to measure the quality of web sites, to choose which pages should be ranked higher. Relevance is still king for SEO, but one new element for search engine optimization (listed by Google directly) is web site speed.
With the speed the world works today, being able to access a site quickly is becoming more of a judgment factor for everyone, both web browsing individuals and the major search engines. Coming to a site that takes a while to load will reduce the chances that that visitor will continue to return. And for the search engines, worse performing web sites will get a hit in SEO value (not a big one, but it still affects rankings).
To find out how to improve your site speed there are a few options available.
YSlow – One that I personally like using is YSlow. Made by Yahoo, this free tool will give you information on which elements of the page are slowest, and gives recommendations on how to refine these issues.
Google Webmaster Tools – This is another free tool that will show all sorts of information on the site, including a graph showing average load time. Hopefully you’re already using this one.
There are several other ways to increase your web site’s loading speed. But realize that this is now something becoming more of a concern for ranking in the search engines.