meta tags: "obsoleted-by" and "obsoletes"

I would like to see standard HTML tags along these lines:

Scenario

Someone published a how-to page for some aspect of fedora20.
Fedora21 is released.
They publish a new version of their how-to page, updated for fedora21.

with the new feature

They add an “obsoleted-by” meta tag to their fedora20 page linking to their new page.
They add an “obsoletes” meta tag to their fedora21 page linking to their old page.


Discussion

Search engines could use this data, when available, to give far more helpful results.

Of course, fact of life, most pages that could benefit from these tags will never be updated to use them, but compliance will improve over time. We always have to start somewhere.

Someone could host a crowd-sourced database of obsoleted-by/obsoletes page relationships. Browsers and search engines could interoperate with it.