microformats

About microformats:

Designed for humans first and machines second, microformats are a set of simple, open data formats built upon existing and widely adopted standards. Instead of throwing away what works today, microformats intend to solve simpler problems first by adapting to current behaviors and usage patterns (e.g. XHTML, blogging).

http://microformats.org/about/

Overview of microformats

People and Organizations

hCard

Calendars and Events

hCalendar

Opinions, Ratings and Reviews

VoteLinks, hReview

Social Networks

XFN

Licenses:

rel-license

Tags, Keywords, Categories

rel-tag

Lists and Outlines

XOXO

For more information see microformats list.