1. An event-handling system which receives events from one or more sources, wherein the sources issue one or more events, where each source associates with each event data including one of a predetermined semantic and an ordered data value, there being predetermined semantics known to each source and predetermined semantics known to each recipient system; said event-handling system comprising: one or more data storage elements for storing received events, each data storage element having an assigned predetermined semantic, wherein each received event is placed in the data storage element having the corresponding semantic of the received event; and means to determine events to be made available to said one or more recipient systems from the one or more data storage elements, the determination being to make available an event if the event has an associated ordered data value within one or more defined data value ranges; wherein the event handling system serves as a semantic patch board to make the event available to the one or more recipient systems based on the semantics of the event and according to the corresponding ordered data value.