This is the W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards.
if you wish to validate specific content such as RSS/Atom feeds or CSS stylesheets or to find broken links, there are other validators and tools available.
Releasing version 0.7.2 of the Markup Validator, a maintenance release updating the codebase for compatibility issues with recent versions of the Config::General perl module, as well as including minor fixes in document types and character encoding support, and documentation.
These are the most recent major changes to this service. See "What's New" for more details. News for this service are also available as an ATOM feed.