Microformats - as pronounced this isn't any Biotechnological word nor its a new language but one among simple web standards that already being adopted by many web organization/ sites. If some of you has done few things on XML, XHTML, RSS or even CSS it's easiest thing you can learn in a day (or even less).

Microformats are set of simple open data formats built upon existing standards that is being adopted widely these days. Its a design principles of formats which is - designed for humans first and machines second, one of the microformats principles along with modularity, embeddability and to some extent portability of information among sources using it. 

 One of the formats that are popular among SEOs / Webmasters or Designers are 'rel' tag which specifies the relevance or relationship to hyperlink. The rel-tag are used for Google algorithm purpose i.e rel="nofollow" or "follow", an attribute to tell search bots not to follow or to follow the link its embodied in respectively.

Technorati is among key players of Microformats in initial stage, that derived from rel="tag" attribute widely seen and used by millions of bloggers worldwide.
[Example - <a xhref="http://technorati.com/tag/tech" rel="tag">tech</a> ]

Microformats are revolutionizing the Web 2.0 standards for better structured blogging, web micro content publishing. It is highly correlated with semantic XHTML or loss-less XHTML.

One of the example is site -  resolio.co's web resume service using hcard microformats standard and thus providing embeddability of resume created to any other web-page this is power of Microformats.

More Readings -  What are Microformats?  | Microformats Cheat Sheet| Real World Semantics