SOA and the hype

I hear so many times the questions "Leaving aside all the slideware, what is SOA?", "What is SOA in terms of technology and products?".
Seems like the big vendors have manages to attract the crowd with the concept, yet they didn't manage (YET) to provide good answers to the technical people.
So, just to clear things out, SOA is not a product specific methodology. It is related to many products that might correlate themselves to SOA.
BUT - There are some fundamental products that are part of the SOA infrastructure and include the following:
ESB / EAI
BPM
Portal
Information intgration (II)
Do you think this is the shortest list or it is not enough?