A Statement consists of the combination of a Resource, a Property, and a value. These parts are known as the 'subject', 'predicate' and 'object' of a Statement. RDF is carefully designed to have the following characteristics. This is necessary since we don't have a GOD to take care of it for us. Since RDF Statements can be converted into XML, they are easy for us to interchange.
Scalability is important.
Properties are Resources Properties can have their own properties and can be found and manipulated like any other Resource. For example, I might want to know if anyone out there has defined a Property that describes the genre of a movie, with values like Comedy, Horror, Romance, and Thriller. I'll need metadata to help with that. For example, most web pages will have a property named Home-Page which points at the home page of their site. So the values of properties, which obviously have to include things like title and author's name, also have to include Resources.