HTML 5 - I wish they'd rethink printers

it specifies everything that needs to be implemented, including obsolete stuff.

Is this for the Everyone Renders Errors the Same Way thing? On the one hand I like identical error rendering… yet on the other hand, everyone doing it differently has helped me convince people to validate their code so many times…

Would be cool if modern browsers ignored obsolete things, but came with a “Garbage” button (could even have a cute little trash can or bag as the icon, complete with wavy stink lines!) users can click to see if the page shows up as expected once they “allow garbage”. Lawlz.

Yeah.

As for motivation for validation, see http://www.whatwg.org/specs/web-apps/current-work/complete/introduction.html#conformance-requirements-for-authors

The choir is already motivated. Stuff breaking in one browser your clients use but working in another browser your clients use— that motivates everyone else : )