After the patent expires, anyone is free to use the subject invention. Computer software inventions can be patentable. In other words, a machine which will not operate to perform its intended purpose would not be considered useful, and therefore would not be granted a patent. Additionally, abstract ideas, laws or products of nature, methods of doing business and pure mathematical manipulations of numbers are not patentable. A trademark is a word, phrase, symbol or design, or combination of words, phrases, symbols or designs, which identifies and distinguishes the source of the goods of one party from those of other parties.
Trademarks also indicate an expectation of quality and consistency in a product.
A service mark is the same as a trademark, except that it identifies and distinguishes the source of a service rather than a product. Normally, a mark for goods appears on the product or on its packaging, while a service mark appears in advertising for the service. Federal registration of a trademark is not required to establish rights in a mark, nor is it required to begin use of a mark. However, federal registration can secure benefits beyond the rights acquired by merely using a mark. Trademarks are also subject to international protection.