SevenCubed - 8:49 pm on Oct 15, 2012 (gmt 0)
Just to back up what I've said above here's a brief extract from an article on the matter.
First Layer — general information typically available from sources like Google
Second Layer — information from medical textbooks and journals
Third Layer — test cases
Fourth Layer — domain-specific information, including specific protocols and procedures that health insurance companies will want to feed Watson. [mdnews.com...]
They are relating information architecture as 4 layers and they specifically mention google by name as being the lowest form of important data.