Microdata [extends](http://www.w3.org/TR/microdata/#content-models) HTML5 in a way that `link` and `meta` elements can be used in the `body` **if** they are used for Microdata. So you are **not** allowed to use *any* `link` element (e.g., `<link href="" rel="" />`) in the `body`, but only those with an `itemprop` attribute.

This extension is currently also included in the HTML 5.1 Nightly (Editor’s Draft)  (see [`link` element](http://www.w3.org/html/wg/drafts/html/master/document-metadata.html#the-link-element) and [`meta` element](http://www.w3.org/html/wg/drafts/html/master/document-metadata.html#the-meta-element)). But as the [Microdata specification became a W3C Note](http://www.w3.org/TR/2013/NOTE-microdata-20131029/) recently, we’ll have to see what happens with this reference.