Linked Data for Humans and Computers - Content Negotiation delivers Data in a Format that can be processed (and was requested) by eh Client. Dependent on the HTTP Accept Header, one can write there
application/rdf+xml then one will get back from the URI the RDF Data. One can also write in the Accept Header
text/html then one will get back the HTML Page.
The GET request via HTTP with an Accept Header
application/rdf+xml goes to the Web Server. The Web Server reads the Accept Header and decides that RDF should be the Response. As the RDF data which is at another URI it therefore sends the Response Code 303 "See Other" as well as the Location which means the new URI of this Data. This comes to the Client and the Client finally access the right URI that has been communicated from the Server and then reaches the right endpoint on the Server to access the RDF Data there. In the same way it is also provided for HTML.
In DBpedia there is a difference between the Resource, Data and Page. There one has the Resource of an Object which really denotes the Resource itself. Now it depends on the Accept Header whether one gets the HTML Page back or another URI with the RDF Data.