<http://schema.org/description>
"Just two weeks ago, I heard Scott Rafer the president and CEO of Feedster say that sponsored ads will be coming to RSS soon.  According eWeek, it looks like its underway.  Currently the only official "^^<http://www.w3.org/2001/XMLSchema#string>
<https://www.seroundtable.com/archives/000765.html>