Is IBM’s Watson an Expert System?
Expert system implies to me rule-based AI. When I was bandying around the conventional wisdom that IBM Watson represented the triumph of the era of machine learning over the past epoch of rule-based AI, and on Quora no less, IBM Watson researcher, and Quora member, Bill Murdock  soundly rejoined that such was not the case …. ;^)
 How does IBM’s Watson work?
BTW, David Ferrucci let slip recently that the IBM Systems Journal will be preparing a special issue dedicated to IBM Watson.