Microformats are the semantic markup formats for (X)HTML pages. Microformats help the robots process the page content. You can explicitly mark the meaning of text blocks and add special blocks to the existing HTML markup.
In this example, the
<div class="adr"> Moscow, Lev Tolstoy, 16 </div>
classattribute is added to the
<div>HTML element to specify the name of the property provided by the microformat. As a result, the robot will be able to render the contents of the element as the value of this property.
Microformats are an open standard used by various services around the world. At the moment there are microformats for several common subject areas, in particular for publishing information about organizations, products, reviews, events and many other entities.
Currently Yandex supports the following microformats:
hCard — Contact information markup (addresses, phones, and so on).;
hRecipe — Culinary recipes markup.
hReview — Reviews markup.
You can check the markup on the site with the structured data validator.
The official site for microformat development: http://microformats.org/wiki.