Networked RDF Graphs extend named graphs with a SPARQL based view mechanism. Briefly, a networked graph, among other statements, contains statements describing the graph itself in terms of SPARQL queries against other graphs. The networked graph then contains some explicitly listed content plus statements computed from the views on other graphs.
Networked Graphs can be used to reuse RDF data in other graphs, to provide application specific views on RDF data, to structure annotation and to define rules (through recursive view definitions).
Read more about networked graphs in S. Schenk and S. Staab, "Networked Graphs: A Declarative Mechanism for SPARQL Rules, SPARQL Views and RDF Data Integration on the Web," inProceedings of the 17th International World Wide Web Conference, WWW2008, Bejing, China, Bejing, China, 2008..