Fascinating overview of hierarchical knowledge vs miscellaneous
   [1]https://archive.org/details/Microsoft_Research_Video_103987
   I'm 1/2 way though this - he finished his main speech, and I'm
   very impressed with his overview of social knowledge vs expert
   knowledge, the history of categorization and classification, the
   pluses and minuses of various systems and you really get a good
   feel for The Future from here. Dating from 2007, it's also a
   fantastic historical look in our Internet history... and it's
   interesting how many of these ideas are incorporated invisibly
   into the web as it is in 2016.... and commercialized. I remember
   when the Semantic Web was "the thing" and I wondered where it
   went. I realized it is subsumed now into the monetized web,
   which to me is a step backwards in a big way from this period of
   hope from 2007. It reminds me of how critical non-commercial
   efforts are.

References

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   1. https://archive.org/details/Microsoft_Research_Video_103987