Microformats and microdata are a way to make certain data machine-readable (by say Google or Bing) by adding semantic attributes.
There are two competing standards, but both work in a nearly identical fashion. Google is throwing its weight behind the Microdata format, but has agreed to also index Microformats.
Microdata is a W3C Draft Specification and a good description of how to use it can be found on schema.org.
The formatted “card” on the right was created with the following microdata markup:
<div itemscope itemtype="http://schema.org/Organization"> <p itemprop="founder" itemscope itemtype="http://schema.org/Person"> <a href="http://pixelpro.biz"> <span itemprop="givenName">Craig</span> <span itemprop="familyName">Creeger</span></a>, <span itemprop="jobTitle">President</span> </p> <p><span itemprop="legalName">Pixel Pro, Inc.</span><br> <span itemprop="address" itemscope itemtype="http://schema.org/PostalAddress"> <span itemprop="streetAddress">1225 Dawn Lane</span> <span itemprop="addressLocality">Woodbury</span>, <span itemprop="addressRegion">MN</span> <span itemprop="postalCode">55125</span> <span itemprop="addressCountry">USA</span> </span></p> <p itemprop="telephone">(651) 361-0457</p> <p><a itemprop="email" href="mailto:craig@pixelpro.biz">craig@pixelpro.biz</a></p> </div>
The formatted “card” on the right was created with the following microformats markup:
<head>
<link rel="profile" href="http://microformats.org/profile/hcard">
</head>
<div class="vcard halfWidthBox" id="hcard-Craig-Creeger">
<p><a class="url fn" href="http://pixelpro.biz"><span class="given-name">Craig</span> <span class="family-name">Creeger</span></a>, <span class="title">President</span></p>
<span class="org">Pixel Pro, Inc.</span><br>
<span class="adr"> <span class="street-address">1225 Dawn Lane</span> <span class="locality">Woodbury</span>, <span class="region">MN</span> <span class="postal-code">55125</span> <span class="country-name">USA</span></span>
<p class="tel">(651) 361-0457</p>
<p><a class="email" href="mailto:craig@pixelpro.biz">craig@pixelpro.biz</a></p>
</div>