This information is outdated and no longer works. Update: July 30, 2018: There is currently a pending schema Type called CssSelectorType that would allow to use content from the current HTML page. However this is currently pending. Once this is approved the below information should work as described again.
A div-Element in HTML is just a section that has no layout. That means, surrounding your main content area will have no visual affect in most themes. However it allows to give the content an ID. For example if you wrote a post the sourcecode of the content could look like this:
No Div
<p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et.</p>
<p>Maecenas sed diam eget risus varius blandit sit amet non magna. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>Here is what it looks like when surround it with a <div>-Element:
With DIV
<div><p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et.</p>
<p>Maecenas sed diam eget risus varius blandit sit amet non magna. Nullam id dolor id nibh ultricies vehicula ut id elit.</p></div>What the DIV-Element allows us is to give it an unique ID that we can refer to:
With DIV and ID
<div id="the_content"><p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et.</p>
<p>Maecenas sed diam eget risus varius blandit sit amet non magna. Nullam id dolor id nibh ultricies vehicula ut id elit.</p></div>With that ID it’s possible to refer to that content in a Rich Snippet.
Usage in a Rich Snippet
For example if you take a look at the Article-Snippet (that comes shipped with the plugin) you can find a property called http://schema.org/articleBody. This property usually inherits the content of a post. To avoid posting your complete content into this property we can instead refer to the main content in a post via the ID so that you don’t need to worry about changing it when the main post content gets changed.
Once the setting called “Surround main content with a DIV so that it can be addressed by snippets.” is active, you will see a new option called “Link to current post content” when you select the value for the property.
