Add semantic markup to templates

[rwanyoike]

Enable people to share content beyond the boundaries of applications and websites. Example: Upcoming events can get picked up by search engines.

Ref. http://semanticweb.org/

[alanorth]

Also relevant (even though it's Facebook): OpenGraph Protocol.

http://ogp.me/

Simple title, description, etc metadata could be pulled easily from Pelican metadata, but authors and stuff might be harder, as it's meant for real people names, not haxx0r names, like some people might be using on the blog.