If you use Crome and have wondered how web site performance is for a page or site, try the newly released Speed Tracer Extension for Crome (https://chrome.google.com/extensions/detail/ognampngfcbddbfemdapefohjiobgbdl)

It helps look at the various parts of the site that are loading and running in the background while the entire site is being rendered.  It seems to be geared more towards website designers, but might be fun for people looking into how a site does what in the background.  Feel free to check it out and grab it if you are using Crome.