We know the various rules for improving Web site performance. But are sites employing them? Which rules are used most? What impact are they having?
The webpagetest.org site (powered by AOL PageTest) has been active for nearly a year now, and has collected performance metrics for more then 20,000 Web pages.
Pat Meenan recently reviewed those results, looking at the cummulative distributions of various metrics and optimization scores. The results are pretty eye-opening.
According to this data, the largest areas for improvement for many sites are:
- Compression (both GZIPing text, and properly compressing images)
- Proper caching
- Using a CDN
Take a few minutes to test your site with WebPageTest. You might be suprised at the results.