Page load time is an important factor in website optimization if only for the fact that if the pages of your site take too long to appear, users can become impatient, stop the load and go to another website. In fact, this is one of the big reasons I was so fond of Google right from the start — their nice clean homepage design had one big advantage over their competitors at the time — it came up quickly and gave me what I wanted right away without making me wait for pictures and other Flashy stuff to load. So we know that fast load time is good for users but what effect does load time have on search engine rankings? This is a question that comes up quite often. Matt Cutts of Google recently asked for topic suggestions for his latest video and this was the number one question.
So, can a delay in page load time affect your search engine rankings? The short answer is yes. Even if load time is not directly a factor in the search engine algorithms, slow load time could lead to a loss of rankings for a website — particularly a very large website. The reason is that in order for your pages to rank to their full potential in the search engine results, search engines need to have accurate information about them. Both the content on the page and the linking structure of the page are important factors in the search engine algorithm.
To illustrate further, consider this diagram to be a rough model of a site’s linking structure. If the page represented by the node highlighted in yellow isn’t crawled by the search engine spider, all the other links that originate from it may not be found either, and that can affect not only the ranking of the top page but also the ranking of all the other pages beneath it, even if the search engine spiders can find those pages another way. This is because they won’t have the full information about how these pages are linked together.
If search engines do not see the full linking structure of a page because it takes too long to crawl the links on your site, linking structure information is not included in the index and the page will rank lower in the search results than it deserves. This is why including an xml sitemap on your site is not good enough to get individual pages indexed and ranked. Search engines have to see how the pages fit together as well.
Search engines cannot give you any credit for something they don’t see. The spiders have a limited amount of time to crawl a site and if page load time is too long, they are less likely to fully crawl your site and that can affect your rankings. Recently, Live.com’s Webmaster Blog did a special four-part series describing special optimization issues for large websites that featured some excellent advice for webmasters with tips for optimizing content, site structure and server configurations. Helping spiders get at your content as quickly and efficiently as possible is an important aspect of search engine optimization so load time should always be given a high priority in any large-scale website optimization project.