A patent represents a grant from the government to an individual for the exclusive right to make, use, import, sell, and offer to sell an invention. In order to obtain a patent in the first place, an inventor must prove to the Patent and Trademark Office that the invention is new, useful, and not merely an obvious improvement over what was already known.
Because a patent provides such strong rights, patent laws require that an inventor apply for a patent within one year of beginning commercialization of the invention, or patent rights might be lost. (Commercialization is generally defined as any public or commercial use of the invention, making a printed publication available to others, or an offer to sell the invention -- even if rejected!)
The types of inventions that may be patented include machines, articles of manufacture, methods of operation and compositions of matter. Video games, virtual worlds and other types of software can be claimed as methods of operation (the processes performed by the software); machines (the computers executing the software); and articles of manufacture (the storage media on which the software is distributed).
