Before 1981, US courts routinely (and almost without exception) struck down patents on all types of software. In two landmark decisions, Gottschalk v. Benson and Parker v. Flook, the U.S. Supreme Court ruled that software was similar to mathematics and laws of nature -- both of which are excluded from being patented -- and therefore was "per se," or inherently, unpatentable. But in 1981, the Supreme Court finally recognized, in Diamond v. Diehr, that just because an invention utilized software, it is not necessarily unpatentable. In the years since 1981, the courts have gradually broadened the scope of protection available for software-related inventions.
Priceline.com obtained a patent on "reverse auctioning," which is at the core of the company's business model -- consumers may bid via the Internet on, for example, airline tickets which may or may not be available, and if the bid is accepted, a purchase transaction is automatically completed. Amazon.com obtained a patent on its so-called "1-click" purchasing technology, whereby users can enter their billing information once and thereafter purchase books and the like via the Internet with one click of the mouse.