When browsing the internet, your browser does a lot to make websites and pages look pretty to you. There's frames, pictures, html, java etc. loaded everywhere in these seemingly simple pages. But, there's more *interesting* information and source codes being loaded in the process of it to while and after your pages appear.
Sometimes, it would be useful to see what component (and their breakdowns) are loading for many reasons including troubleshooting, code debugging & reverse engineering and security snooping!
Download and check out DebugBar (http://www.debugbar.com) for Internet Explorer. Once you've loaded the software, click on View (Tools), Toolbars, click on Debugbar and you'll see a left side frame showing the technical breakdown of the website you loaded in your browser.
NOTE: Although the website doesn't explicitly mention support for Vista and IE7, i've tried and works well.