Q. So how do you know if you are a pirate.
A. You don't think about things like that ... ya just Arrrrrrr !
The YSlow extension for Firefox is an addon that requires the popular Firebug Extension. If you don't use firebug and you do your own web development, you really owe it to yourself to check it out. It's the bomb. Anyway ... YSlow adds some features to Firebug that allow you to test the performance of your web pages. YSlow is brought to you by the Yahoo Developer Network. The addon includes great web documentation.