Speed now matters in SEO, according to an announcement on the Google Webmaster Central Blog by by Amit Singhal, Google Fellow and Matt Cutts, Principal Engineer, Google Search Quality Team.  The search engine behemoth revealed that it will start factoring in website speed (how quickly a website responds to web requests) into its search results algorithm – a decision based on split seconds it thinks have no business being wasted.

Google recently added Site Performance and Page Speed suggestions in Google Webmaster Tools accounts and actually indicated it would start tinkering with the idea a of speed as a ranking factor last year, and soon realized they were onto something. According to Search Engine Land, Google sees this as a win for both its interests and those of the wider web.

In addition to the numerous studies over the years that show Internet users prefer fast pages, Singhal says Google ran its own testing on how users respond to page speed, including experiments on Google.com. Singhal and Cutts point to a June 2009 blog post on the Google Research Blog that talked about how Google purposely slowed down its search results to measure the impact on search behavior.

All other things being equal, more usage, as measured by number of searches, reflects more satisfied users. Our experiments demonstrate that slowing down the search results page by 100 to 400 milliseconds has a measurable impact on the number of searches per user of -0.2% to -0.6% (averaged over four or six weeks depending on the experiment). That’s 0.2% to 0.6% fewer searches for changes under half a second!

“When we slow our own users down [on Google.com], we see less engagement,” Singhal says. “Users love fast sites. A faster web is a good thing all around.”

Speed makes for an interesting SEO factor, because it’s one of the few that directly rewards website performance (as opposed to design factors like site architecture and keywords). And it’s a reminder of what good search engines try to do: give searchers quick, accurate access to the best and most relevent information they’re looking for. Slow sites inhibit that goal.

So here’s a few tips for keeping your website humming:

1. Consider SEO ramifications before adding heavy, unnecessary features — especially if the benefits of such features are unproven (we think a sleek, uncluttered web design looks better, anyway).

2. Tinker with tools. Google has a bag full of tricks that can help “make the web faster” in addition to the specific page speed suggestions provided in Google Webmaster Tools.

3. Limit HTTP requests. According to the Yahoo Developer Network: “80% of the end-user response time is spent on the front-end. Most of this time is tied up in downloading all the components in the page: images, stylesheets, scripts, Flash, etc. Reducing the number of components in turn reduces the number of HTTP requests required to render the page. This is the key to faster pages.”