Facebook converts webpages into Open Graph objects using RDFa Core markup if present (Open Graph protocol) with some fallbacks in place for missing data (e.g. if no
og:image search for a suitable
<img> instead. The Facebook plugin for WordPress converts information stored for your site, post, and authors into Open Graph protocol markup for the appropriate WordPress webpages and passes the results through a filter. You might act on the filter, you might write something similar as a separate plugin, or you might use a different plugin for such a purpose. You should test the results of whichever implementation you choose against the Facebook URL debugger to make sure the appropriate values are present.
An Open Graph action is a programmatic way to post new content to your Facebook timeline with more context. When you click a Like Button you are publishing an og.likes action on the object represented by the current webpage.
The Facebook plugin for WordPress supports associating a Facebook application with your WordPress site. Facebook applications can define their own custom Open Graph objects and actions or use one of Facebook's built-in objects and actions for more consistency across applications.
Facebook supports a news.publishes Open Graph action for authors publishing new Open Graph article objects. The Facebook plugin for WordPress treats individual WordPress posts as article objects; you could override in a filter. The news.publishes action requires additional setup for the Facebook application associated with your WordPress site including Facebook approving the action and its capabilities. The plugin holds back switching to this more advanced method of publishing new articles to an author Timeline until a site admin confirms everything is set up correctly by checking the checkbox.