The main type of patent, a utility patent, covers inventions that function in a unique manner to produce a utilitarian result. Examples of utility inventions are VelcroŽ hook-and-loop fasteners, new drugs, electronic circuits, software that is tied to some form of hardware, semiconductor manufacturing processes, new bacteria, newly discovered genes, new animals, plants, automatic transmissions, Internet techniques and methods of doing business (provided physical things are involved), and virtually anything else under the sun that can be made by humans. To get a utility patent, one must file a patent application that consists of a detailed description telling how to make and use the invention, together with claims (formally written sentence fragments) that define the invention, drawings of the invention, formal paperwork, and a filing fee. Sometimes the state of the art, rather than the nature of the novelty, will determine whether a design or utility patent is proper for an invention. If a new feature of a device performs a novel function, than a utility patent is proper. According to the USPTO in 2009, there were 456,106 utility patent applications. Patent law is designed to promote innovation in "science and useful arts." It's right there in the first Article of the Constitution: in order to be patentable, an invention needs to be useful in some way. Utility patents expire 20 years from the date of filing.
The Japanese commissioner in Washington DC in the 1900's studying the American patent system said, "We have looked about us to see what nations are the greatest, so that we can be like them... We said, 'What makes the United States such a great nation?' and we investigated and found that it was patents, and we will have patents."
In celebration of Noah Webster's Birthday (October 16, 2009), we have prepared an updated website. 
