1. A method for locally caching and sharing downloaded data between a plurality of client nodes, the method comprising: (a) providing a plurality of client nodes interconnected by a network, each of the plurality of client nodes sharing a shared addressable memory space of a globally addressable data store and including (i) an interface for accessing the network, (ii) a local volatile memory device for volatile storage, (iii) a local persistent storage device for persistent storage, and (iv) a subsystem for mapping at least a portion of the shared addressable memory space to a portion or all of the volatile and persistent storage to provide thereby addressable volatile and persistent storage accessible by each of the plurality of client nodes; (b) storing on each node an instance of a control program for manipulating caches of downloaded data to provide multiple, ditributed instances of the control program; (c) interfacing each instance of said control program to the globally addressable data store; (d) operating each instance of said control program to employ the globally addressable data store as a memory device; (e) storing data downloaded by any one of the plurality of nodes in the globally addressable data store; and (f) retrieving the downloaded data stored in the globally addressable data store by a different one of the plurality of nodes.