YSlow analyzes web pages and tells you why they're slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with the popular Firebug web development tool. YSlow gives you:

  • Performance report card
  • HTTP/HTML summary
  • List of components in the page
  • Tools including JSLint

Download HERE
Visit also the homepage of the team behind this tool: Yahoo!'s Exceptional Performance Team

You should not take too much time to guess that I am currently optimizing my homepage :-)
Be careful, running this tool more than 5 times make my Firefox crash ;-)

Some statistics:
Some useful links
Be careful! a lot of host get pretty low metering (just test your favorite internet site), but are still very fast -> this tools do not tell You their infrastructure: memcache server, multiple db server, multiple file server for static content and so on.

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