W3 docs started out, and I would argue, continues to be most relevant to people whose work it is to implement a browser.
Certainly, you can use them to learn how to use the various HTML, CSS, and JS standards, but this is where MDN - and even the Chromium and Webkit resources - are leaps ahead with practical examples you can use in your own code.
Really, I wasn't sure when I wrote that. Refsnes Data, who owns/runs the site, isn't affiliated with the W3C in any official capacity that I know of.
I was thinking more of a story I heard on an old episode of Hypercritical where John described first learning HTML and the rest through a combination of (mostly) O'Reilly books and reading the specs themselves.
While I suppose this passed muster in the early/mid 90's, I would repeat my earlier claim that the specs nowadays are more for implementers, and not something really well suited to teach you how to use the various languages and tools.
Potentially losing what is perhaps the most approachable reference for this purpose would be terrible for everyone.
W3 docs started out, and I would argue, continues to be most relevant to people whose work it is to implement a browser.
Certainly, you can use them to learn how to use the various HTML, CSS, and JS standards, but this is where MDN - and even the Chromium and Webkit resources - are leaps ahead with practical examples you can use in your own code.