1. A method for providing at least one client access to a network semantic graph distributed among a plurality of semantic servers wherein the network semantic graph comprises concept instances and relations between the concept instances, the method comprising: receiving first data including semantically distributed annotations from distributed data sources in communication with the plurality of semantic servers; based on the first data including the annotations, linking the concept instances using the relations; storing the concept instances and relations as a local semantic graph comprising a part of the network semantic graph; creating at least one subscription of interest over the network semantic graph in response to a request from the at least one client; collecting second data from the distributed data sources based on the at least one subscription; semantically annotating the second data; updating the local semantic graph based on the semantic annotation; sending alerts 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.