Killer app

In marketing terminology, a killer application (commonly shortened to killer app) is any computer program that is so necessary or desirable that it proves the core value of some larger technology, such as computer hardware, a gaming console, software, a programming language, a software platform, or an operating system. In other words, consumers would buy the (usually expensive) hardware just to run that application. A killer app can substantially increase sales of the platform on which it runs.

One of the first recognized examples of a killer application is generally agreed to be the VisiCalc spreadsheet for the Apple II series. Because it was not available on other computers for 12 months, people spent $100 for the software first, then $2,000 to $10,000 on the Apple computer they needed to run it.BYTE wrote in 1980, "VisiCalc is the first program available on a microcomputer that has been responsible for sales of entire systems", while Creative Computing's VisiCalc review was subtitled "reason enough for owning a computer". Others also chose to develop software, such as EasyWriter, for the Apple II first because of its higher sales, helping Apple defeat rivals Commodore International and Tandy Corporation.

Lotus 1-2-3 similarly benefited sales of the IBM PC and compatibles, just as VisiCalc did for Apple sales. Noting that computer purchasers did not want PC compatibility as much as compatibility with certain PC software, InfoWorld suggested "let's tell it like it is. Let's not say 'PC compatible,' or even 'MS-DOS compatible.' Instead, let's say '1-2-3 compatible.'" Another killer app is WordStar, the most popular word processor during much of the 1980s. Once the Internet became more widely available to consumers, email was seen as a killer app that drove people to purchase computers, even though email is a genre of applications rather than a single "app."

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