33. A semantic network providing a network semantic graph comprising concept instances and relations between the concept instances, the semantic network comprising: a plurality of semantic servers in communication with each other and with distributed sources, wherein each of the plurality of semantic servers comprises: an input/output module to receive data including semantically descriptive annotations from the distributed sources; a processor programmed to process the data based on the semantically descriptive annotations of the data to form a local semantic graph that associates the concept instances with each other using the relations, to create at least one subscription of interest in response to a request from at least one client and to send at least one alert to the at least one client based on updates to the local semantic graph matching the at least one subscription of the at least one client; and memory for storing the local semantic graph; wherein each local semantic graph of each of the plurality of semantic servers comprises a portion of the network semantic graph distributed across the plurality of semantic servers.
44. The semantic network of claim 33 , wherein the processor is further programmed to receive a query from at least one client; to search the network semantic graph based on the query; and to send the at least one client a response based on a result of the searching.