When allowing users on your website to do Likes, facebook looks on the page to try to extract some revelant information to improve the listing in Facebook, this add-on makes presenting to facebook the information you want rather then it being a lottery as to what gets published. The Add-on allows you to control the page title, description, and even the image that facebook will see, to make it more versitile the add-on allows you to set defaults to make sure that there is always data to list. The defaults are set in the admin control panel, you can set the default page Title, the page Description, and the default image to use.
On any page these values can be overridden with different values by adding attributes to the page and setting a different value.
There is an 'Order of precedence' Applies to the Image, Title and Description
For these elements there is an order that the value is selected. If you have set a page level attribute that is used, otherwise the page value is used, otherwise the meta value is used, finally the site wide default is used.
This Add-on is defined as Beginner because it is extremely easy to get started. But also gives you the flexibility to define exactly what you want Facebook to see.