These days you can't be too careful about what you download. A new Firefox add-on from Florian Queze called View Dependencies takes some of the guesswork out of knowing the content of a Web page, and the source of that content.
After you download the free add-on and restart Firefox, you'll see a Dependencies tab when you click Tools > Page Info to view information about the page that's currently open. The tab lists the files on the page, their URL, and their size. (Note that on at least one page I tested the file size was not available.)
I used View Dependencies to check about a dozen popular home pages, and the two with the most individual files were Amazon.com with 150, and ESPN.com, which was comprised of 119 separate files when I last visited. The page with the fewest files listed was the classic Google home page, which does its magic with a total of two files. Compare that to the 27 files downloaded at my customized iGoogle page, 29 at Gmail, 18 at Wikipedia, and 39 at the View Dependencies download page.
You can right-click an entry and choose Open in New Tab or Open in New Window to view just that one file. Other context-menu options let you copy the entry, copy just the URL, or just the host name.
Monday: organize a cluttered Outlook inbox.