Significant attainments become lost in the mass of the inconsequential
Vannevar Bush wrote this in his famous 1945 essay, As we may think, where he talks about the Memex (or memory extender), the source in which much of the way we organize or conceptualize knowledge today is said to be inspired (hypertext, Internet, networked knowledge)
In a world soaked with information, which can be accessed and retrieved in various ways almost instantly, the work of the teacher cannot remain the same, lecturing what has been said countless times, but to show what is essential and significant, model ways of connecting/relating information and thinking it critically, so as to attain knowledge and become able to use it in the real world.