Unlike other content blocks that usually let you show contents of one field, this one will allow you to use any field, at the same time. This is aimed at letting you “compose” content blocks using third party services which provide a shortcode or some form of embed code.
Let’s say you have installed a plugin that shows a twitter feed, and it also provides a handy shortcode to use it anywhere. You could implement it in the single listing page, by first creating a new listing custom field for the “Twitter Username”, and then, using the new “Shortcode” block, set it’s contents to:
[twitter-widget username="[[twitter-username]]" title="[[listing-title]]" show="10"]
There’s also a new shortcut to easily append a listing field here — just type “@” or “[[“ and a list of suggestions will pop up. Example: