XHTML validation via RSS

Ben Hammersley’s new XHTML Validator to RSS source tool is one of those ideas that’s so simple and yet so brilliant that you can’t believe someone hasn’t thought of it before. It let’s you subscribe to an RSS feed of validation errors on a page – if the page is valid you won’t get any updates, but slip up and the feed will tell you all about it. Ben’s service hooks directly in to the W3C validator using their under-publicised XML interface.