Vapourware is a term for computer products that a company announces, but doesn’t put into production. This might seem a straightforward concept, but arguments over what counts as 'vapourware' have continued for years.

There are several reasons a prototype may not have gone into production, the most common of which is that a manufacturer or software house keeps on announcing the imminent launch of a new product which is a long way from actual production; sometimes it doesn’t exist at all. In other words, the term describes a deliberate attempt to mislead the buying public.

But the failure of an announced product to reach the market isn’t always a fraud. By the time a product is ready for market, more than one company has found that the technology already exists. There are also cases where an internal project was common knowledge throughout a large corporation, as well as to business partners, and even third party software developers and technical journalists. Often, companies demonstrated working prototypes to invited audiences, but made no formal announcement when they later dropped the product. In this respect, they are all vapourware: tantalising glimpses of what might have been had circumstances been different. The comparable terms “hardware” and “software” are not pejorative, and neither are the terms “firmware”, “shareware” or ‘freeware’. The fact that these designs haven’t been tested in the marketplace doesn’t mean that they have had no impact. Ideas for products, rather than products themselves can have influence far beyond that expected.

Some of the hard evidence in the form of actual prototypes has long been consigned to the dustbin of history, leaving photographs as the only record. Rumours surface with no supporting evidence, and finding that evidence has often entailed arduous detective work.

A history of vapourware provides an entertaining view of an alternate world, of products that could have been available, or others that were just fantasy. Was a housewife ever meant to store recipes in a 16-bit computer in 1969? The stories behind individual examples of vapourware confuse the idea of progress over time and provide an alternative history of computing, It’s a story of missed opportunities over the decades, from mainframes and minicomputers, to personal computers and mobile computing, up to the present day.