It’s pretty hard to write something interesting about the development of HTML standards, but that’s exactly what Paul Ford did in his New Yorker piece which goes through the history of the W3C and the development of the HTML5 standard. Go read the whole thing and in the meantime, here’s a few snippets.
Validity, in this scenario, is an ideological construct. The promise is that by hewing to the rules put forth by the W3C, your site will be accessible to more people than would a less valid page. Both pages work fine for most people; browsers are tolerant of all sorts of folderol. The ultimate function of any standards body is epistemological; given an enormous range of opinions, it must identify some of them as beliefs. The automatic validator is an encoded belief system. Not every Web site offers valid HTML, just as not every Catholic eschews pre-marital sex. The percentage of pure and valid HTML on the web is probably the same as the percentage of Catholics who marry as virgins.
On how the web is evolving:
The Web started out as a way to publish and share documents. It is now an operating system: a big, digital sensory apparatus that can tell you about your phone’s battery life, record and transmit your voice, manage your e-mail and your chats, and give you games to play. It can do this all at once, and with far less grand of a design than you might assume. That’s the software industry: it promises you an Ellsworth Kelly, but it delivers a Jackson Pollock.