This is with reference to:
http://googlecode.blogspot.com/2011/01/go-daddy-makes-web-faster-by-enabling.html
But I still don't know how it works the in background to dynamically optimize pages.
One more thing I could NOT understand why "Cached subsequent requests are slow" ?
PageSpeed mod_pagespeed is a module for Apache server which is just like a plug in, and since Apache is different from IIS, it cannot be installed on IIS servers.
As for what it does, it does multiple things:
So this module is pretty cool. It can really speed up the performance of the sites. One downside however is that it uses much more CPU resources on the servers.
Hope this helps.