In my opinion, to setup an entire semantic web, it is necessary for the web to understand the whole vocabulary that human beings use. But actually the vocabulary is such a big and intelligent things and there is no a good way for the web to understand (Maybe such procedure will take a long time). Can I pick up all the explanations from the dictionary and input to the web so the web has a basic understanding about the vocabulary it will meet with? No, I think. The essential of Semantic Web is how to understand, not how much the web understands.