Is there an easy explanation about how to interpret the waterfall?
http://www.webpagetest.org/result/100625_HQX/1/details/
It looks to me like the Feedjit script is really slowing down my sites load and start to render time??
The blue line shows you the document completion time, whereas the green shows the start render time. Your rendering starts well before the feedjit script even loads, so it is not affecting your start render time. That script however is slowing down your document completion time. If you can, try to defer the script from loading until the document is complete using javascript and the window.onload event (if you need help with this try the webdeveloper.com forums). You also really need to look into a script, or manually combine the different .js files into one file. As you can see from the waterfall, that is taking up quite a bit of your time. I’ll try to examine it more closely later on.
It’s a bit old but Davev Artz did a video walkthrough on reading the waterfalls: http://www.artzstudio.com/2008/07/optimizing-web-performance-with-aol-pagetest/
Aptimize also created one recently that I haven’t had a chance to look at yet: http://www.youtube.com/watch?v=JTwges72rdg