1. A method implemented on a computing device by a processor configured to execute instructions that, when executed by the processor, direct the computing device to perform acts comprising: receiving a content request from a content requester; retrieving the requested content from a content source; processing, by the processor, the retrieved content to provide an abstract content model providing at least one directional graph comprising nodes that represent components of the content and edges that represent relationships between the nodes, wherein the directional graph further comprises a directional graph G=(N, E) that satisfies the following condition, where N stands for “node” of G and E stands for “edge” sets of G: a node set N can be divided into several subsets as N j, i=1 . . . m where N = ⋃ i = 1 m ⁢ N i and N i ∩N j =Φ, ∀i,j=1 . . . m,i≠j; ∀a=(n s ,n e )εE, there exists a pair of 1≦i<j≦m such that n s εN i and n e εN j ; and ∀a=(n s n e )εE,s≠e; processing the abstract content model to select an optimal delivery plan the use of which will permit requested content to be delivered to the content requester; and processing the abstract content model to provide deliverable content in accordance with the selected delivery plan.
1. A method implemented on a computing device by a processor configured to execute instructions that, when executed by the processor, direct the computing device to perform acts comprising: receiving a content request from a content requester; retrieving the requested content from a content source; processing, by the processor, the retrieved content to provide an abstract content model providing at least one directional graph comprising nodes that represent components of the content and edges that represent relationships between the nodes, wherein the directional graph further comprises a directional graph G=(N, E) that satisfies the following condition, where N stands for “node” of G and E stands for “edge” sets of G: a node set N can be divided into several subsets as N j, i=1 . . . m where N = ⋃ i = 1 m ⁢ N i and N i ∩N j =Φ, ∀i,j=1 . . . m,i≠j; ∀a=(n s ,n e )εE, there exists a pair of 1≦i<j≦m such that n s εN i and n e εN j ; and ∀a=(n s n e )εE,s≠e; processing the abstract content model to select an optimal delivery plan the use of which will permit requested content to be delivered to the content requester; and processing the abstract content model to provide deliverable content in accordance with the selected delivery plan. 9. The method of claim 1 , wherein there are multiple different types of edges.