Well (sorry Paul!), I disagree. CEP is neither a process nor a service; CEP is a concept architecture for processing complex events. (I have advocated a CEP functional reference architecture, as most readers know.)
To illustrated this point, let’s take a quick look at another functional reference architecture (or, if you perfer, a conceptual architecture), distributed computing.
Is distributed computing a service or a process?
Of course, it is neither a process nor a service, distributed computing is a generic architectural pattern (or style) for processing distributed data, generally across a network.
The same question can be asked of SOA.
Is SOA a process or a service?
Again, the answer is almost identical.
SOA is an architectural style (subclass) of distributed computing.
Now, is CEP a product or a service?
CEP is an architectural style (or pattern) for processing complex events.
CEP is neither a process nor a service.
On the other hand, there are component of a CEP solution that can be represented as a stand alone process or a service. The same can be said of EAI, SOA, and other subclasses of distributed computing architectural styles and patterns.