Automatic Tutors

In The Echo, a quite long ago talk with Daniel Hillis about the web, about knowledge and its evolultion.   Also the realm of 'automatic tutors' and what they could mean when having access to universal knowledge.  How are these like bots and virtual assistants emerging today?  We certainly have stored much more knowledge today, but its hardly universal or complete.  Semantic webs and Linked Data are still not common in industry.   Why?    "Aristotle" (the Knowledge Web)  by W. Daniel Hillis  ....