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.