These meta data are used by Facebook and Google to collect better information by your products and blog posts.
Users, NOTE: if you have your Joomla installation in a subdirectory, if you add URLs for adding metas, you must add subdurectory name to the URL Path too. In the URLs manager write something like /subdirname/your-defined-page-for-meta.html. If you don't add subdirectory name to the URL path, the added metas will not be attached to your defined page despite you add them in URLs and meta manager!
The main issue I have is with the support forum. Author doesn't respond even after fair waiting and prompting, therefore use at your own risk.
Thank you for the review.
All is OK now. :)
So keep it up!
A great thing would be to add the possibilty of making an open graph tag applying for a category or a component (all urls created by the component should contain these tags)