warnings on outdated specs/docs

it was mentioned on twitter[1] that someone was referencing this doc
www.w3.org/TR/2006/WD-WCAG20-20060427/Overview.html

This is but one example of many, where outdated documents are consumed and
referenced by all sorts of people, this is obviously bad for many reasons.

some other w3c wg's have started to put warnings on outdated material and i
think it is something we should be doing.

[1] https://twitter.com/SteveBuell/status/580421155439419392
--

Regards

SteveF
HTML 5.1 <http://www.w3.org/html/wg/drafts/html/master/>