Deployed CDN Here
One of the first things I have seen when looking at YSlow and Pingdom reports is the need to serve files that change little from a CDN (Content Delivery Network). Using the CDN module for Drupal 7 worked on one site, but here at PcHousekeeping it just wouldn't play right. I found a good tutorial by Wim Leers the developer of the CDN module and it encouraged me to use commercial CDN service. The article encouraged, and I went with, Amazon CloudFront. It's supposed to be cheap and I already had an account with AWS (Amazon Web Service).
It has already improved my score with Pingdom and YSlow so we will monitor it over time and see if it's all worth while for a site that doesn't get a lot of traffic. I needed to do it if for no other reason than a training exercise.
The first site I configured with the CDN module was balnu.com which is just a lab rat at this time. I used the "fake CDN" concept described at RUNEFORGE. This idea uses subdomains off of the main site domain to fool the browser into downloading more than 2 components at a time. This idea also helps more files to be loaded cookie-free which is supposed to be a good thing.