Microdata has been one of the top features requested for Joomla! from marketers! Web semantics are moving forward with the aim of making a more useful web which will relate everything on the web by ‘meaning’ in addition to raw ‘textual data.’
This feature allows many aspects of the content rendered by the Joomla! CMS to be explained to search engines using semantic information. For example, breadcrumbs can be marked up as such, and used in search results to give a visual representation of topics and categories”.