Microdata

Microdata enables it to describe Metadata in HTML and give a meaning to the markup. That’s handy for Crawler or other integrations. For instance, can an E-Mail render a “discount” (or something else) in the client.

<div itemscope itemtype="http://schema.org/DiscountOffer">
    <meta itemprop="description" content="20% off" />
</div>