ConceptNet is a freely available commonsense knowledgebase and natural-language-processing toolkit which supports many practical textual-reasoning tasks over real-world documents right out-of-the-box (without additional statistical training) including
The W3C's Semantic Web project has been described in many ways over the last few years: an extension of the current web in which information is given well-defined meaning, a place where machines can analyze all the data on the Web, even a Web in which machine reasoning will be ubiquitous and devastatingly powerful. The problem with descriptions this general, however, is that they don't answer the obvious question: What is the Semantic Web good for?
F. Shi, J. Li, J. Tang, G. Xie, and H. Li. The Semantic Web -- ISWC 2009: 8th International Semantic Web Conference, Chantilly, VA, USA, volume 5823 of Lecture Notes in Computer Science, Springer, Berlin, (2009)