Abstract: A method of servicing complex interests for a plurality of client applications or subscribers (8-10), includes specifying a plurality of complex interests from the applications or subscribers (8-10). At least one of the complex interests is formed from a plurality of constituent simple interests. A plurality of constraints are specified over the constituent simple interests. A plurality of event filters are specified from the applications or subscribers (8-10). A plurality of simple event filters (5), which match the constituent simple interests, are employed as at least one of the event filters. A set of events, which matches the at least one of the complex interests, is detected. One application or subscriber (8-10) is notified when the set of events is detected. At least one server (7) is employed to detect the set of events and notify the one application or subscriber (8-1) when the set of events is detected. The at least one server (7) is scaled.