Sam Ruby on Rev Canonical

[The short list of grievances][link]: Twitter doesn’t support it, and may never. HTML5 omits `rev` entirely. Atom uses the `self` attribute for the very purposes that `rev=”canonical”` might be used for.

[link]: http://intertwingly.net/blog/2009/04/14/Canonical-Reverse-Or-Wisdom-Defying-Shorturl “Sam Ruby: Canonical Reverse Or Wisdom Defying Shorturl?”