I have written before about the importance of the Semantic Web. Basically, it converts the web from mountains of text into a database of discrete pieces of information. The result is that the Semantic Web can create relationships among the pieces of information that were not possible before, giving your search context. Look at it this way. If you search for Leonardo da Vinci, Google V 1.0 returns rows and rows of "hits" in which the text string "Leonardo da Vinci" appears. You then dig through them and develop relationships in your own mind among them, about, for example, LdV and the Renaissance, how LdV's inventions have inspired others, and so on. But you need to develop these relationships on your own.
As of Google's Knowledge Graph, let's call it Google V 2.0, your search returns not just the presence of that text string, but also these relationships as well. That is, it shows you context and other references related to your search that you might find helpful, automatically generating a knowledge map of interrelated facts and concepts. The hope is you will spend less time slogging through all that text, and more time actively engaged in connectiveness of the information. The Semantic Web won't give us less information to deal with. But it potentially will make the information we deal with much more relevant to what we are looking for.