About 8-9 years ago (around 2011) when I was studying knowledge management, a question pop up in my mind.  In the past, we used to learn from the past, which I call it knowledge of the past, and majority of people were just doing that.  The way it worked was someone like the teachers and professors, or the professionals, they learned the knowledge, and create a course or training classes, and pass on the knowledge to the others, to classes of students, or to the next generation.  People in the past decades had been surviving like that.  Go to the college,