When you create your RSS feed for your users, you analyze the feed to confirm that everything works and its proper RSS...or so you think.
Thats where the RSS Validator extension comes in. The extension takes an existing RSS feed displayed on the screen and validates it against the W3C RSS Validator.
Click on a sample RSS Feed and display the RSS in Firefox. Right-click to get the context menu and select Validate RSS. The extension will take the current URL and validate it at the W3C site, immediately reporting on what was right or wrong with the RSS.
The extension is very basic and extends the developers validity checks against the W3C standards, which, in my book, is a great help.