Killer Apps

A killer application (commonly shortened to killer app), in the jargon of computer programmers and video gamers, has come to mean any program, particularly a minor one, that is ingeniously coded or unexpectedly useful. Originally, and more broadly, "killer app" has been used to refer to any computer program that is so necessary or desirable that it provides the core value of some larger technology, such as a gaming console, software, operating system, or piece of computer hardware.
One of the first examples of a killer application is generally agreed to be the VisiCalc spreadsheet on the Apple II platform (see picture). The machine was purchased in the thousands by finance workers (in particular, bond traders) on the strength of this one program.
In this sense, a killer app substantially increases sales of the hardware that supports it: the next example is another spreadsheet, Lotus 1-2-3. Sales of IBM's PC had been slow until 1-2-3 was made public; the IBM became the best-selling computer only a few months after Lotus 1-2-3's initial release.
What's more, a killer app can provide an important niche market for a non-mainstream platform. Aldus PageMaker and Adobe PostScript gave the graphic design and desktop publishing niche to the Apple Macintosh in the late 1980s, a niche it retains to this day despite the fact that PCs running Windows have been capable of running versions of the same applications since the early 1990s.