1. A method of profiling event streams received from an event bus, the method comprising: receiving input events from one or more input event streams emitted to the event bus; receiving query registration-related events from a registration event stream emitted to the event bus, the query registration-related events being associated with actions taken with respect to queries performed on the one or more input event streams; developing event-based profiles by subjecting the received input events to a profiling complex event processing (CEP) engine, the profiling CEP engine operating in connection with processing resources including at least one processor, the event-based profiles including data mining related characteristics and/or statistical characteristics for each said input event stream; developing query-based profiles by subjecting the received query registration-related events to the CEP engine, the query-based profiles including data indicative of how relevant the queries performed on the one or more input event streams are and/or how those queries are relevant to the one or more input event streams on which they are performed; and storing the event-based profiles and the query-based profiles to a non-transitory computer readable storage medium, wherein query registration-related events are generated at least each time a query on the one or more input event streams is registered or deregistered.