<http://schema.org/description>
"That's right, from the Google AdSense: What's New page:\nTo provide even more value to your users, and to help you further monetize your web pages, we're allowing publishers to place up to three ad uni"^^<http://www.w3.org/2001/XMLSchema#string>
<https://www.seroundtable.com/archives/000834.html>