In early 2009, the web community was asked if they thought there still was a strong motivation for validation. Here are some reasons they mentioned:
Validation as a debugging tool
While most Web browsers do an increasingly good job of parsing even the worst HTML “tag soup”, some errors are not always caught gracefully. Very often, different software on different platforms will not handle errors in a similar fashion, making it extremely difficult to apply style or layout consistently.
Using standard, interoperable markup and stylesheets on the other hand, offers a much (more…)