In previous sections, I talked about the importance of web site performance on user experience and attention. My derived rule of thumb was to keep your pages under 2 seconds. All general speed studies I have seen validate this target. If you can deliver your pages in under a second, users will consider your site "fast", 2 seconds is good, 5 seconds is slow, and anything beyond that risks losing the audience.
With the announcement by Google in an official blog post that web site speed was a new influence on search rankings, much attention was added to page performance. Studies estimated that 50% of the pages from the US to the US were delivered in around 3 seconds. In order to be considered fast (10%), a page had to deliver in less than a second. With the continued shift to mobile web access, this influence is likely to grow.
In this section I will go into the components that make up site performance and why you should keep them in mind when creating a web site and experience. As mentioned previously, a good place to start is Google PageSpeed and Firefox Firebug. Both tools can help you identify quick fixes to architectural problems. Once you exhaust these starters, I will touch on some additional areas to consider for performance improvements.
One caution, general analysis commentary offered on the web is done with the assumption that global delivery is consistent. The studies are done from a single local user location. This type of study is never accurate. If you have a global audience, it is important to monitor the performance of your site globally. You can sample your web site from the outside world using tools like Keynote or Gomez. Each of these can help you guarantee quality of experience for your visitors.