Hype is the coin of the realm in the technology business. If you listen to vendors and the media, it may sometimes seem as though every new product, service, concept or even security threat will be the Next Big Thing. Some live up to all the fuss, but many don't -- and some fail spectacularly.

Take the Michelangelo virus, the subject of a media frenzy 15 years ago. March 6, 1992, was the day that the dreaded virus was supposed to strike. Journalists went overboard covering this virus, which had supposedly burrowed itself into hard drives around the world throughout 1991 and was set to start destroying data on March 6, the birthday of the famous artist.

It didn't happen that way, of course: Damage was minimal. But in honour of Michelangelo's birthday, we thought we'd track down history's biggest technology flops.

Here we nominate 21 of our favourite overhyped failures, presented in alphabetical order.

The top flops

First we present the biggest flops, in which the hype-to-success ratio was farthest out of whack. The 14 products and technologies listed here weren't all bad. In fact, some were quite good but were either too far ahead of their time or were victims of overblown expectations. Others, of course, were downright lousy.

Apple Newton

In 1993, Apple hyped its Newton PDA as only Apple can, with clever advertising and relentless word-of-mouth campaigns. While the device's physical size was gargantuan by today's standards, it was full of features, such as personal information management and add-on storage slots, that remain essential parts of today's mobile devices.

So why did Newton flop? One reason was the ridicule heaped on it by talk show comedians and comic strips (most notably "Doonesbury"), which focused on the supposed inaccuracy of the handwriting recognition.

Also, Newton was expensive -- about US$700 for the first model and as much as US$1,000 for later, more advanced models. In addition, Newton was arguably ahead of its time.

Still, before it faded away in 1998, Newton paved the way for PDAs, which led, in turn, to today's smart phones. In particular, the smaller, cheaper Palm Pilot, which was released in 1995 and became a runaway success.

To clarify, the official name of Apple's product was the MessagePad; Newton was really the name of the operating system. But Newton captured the public's imagination, so that's what the device was popularly called.

Digital audio tape

Take yourself back to the mid-'80s when analogue tape cassettes were still a common method of purchasing and transporting music. They were easier to manage than old vinyl LPs but they didn't sound as good.

So it was logical that digital audio tape (DAT), developed by Sony and Philips, would become a Next Big Thing: It was digital, didn't use compression and used higher sampling rates than audio CDs. Indeed, a quick office poll found that at least two Computerworld U.S. editors put off purchasing CD players because they were waiting for DAT to take off.

Alas, this was another good idea that failed miserably. First, there was the matter of competing formats. Audio CDs, which were introduced around 1983, were starting to be embraced by consumers. Then the recording industry became concerned that DAT would encourage piracy because it could be used to make near-perfect digital copies of recorded music. The industry convinced Congress to pass the Audio Home Recording Act in 1992, which required strong -- some might say Draconian -- copy protection for DAT. It also required that DAT equipment vendors pay royalties to the recording industry.

That stumbling block cleared the way for audio CDs. DAT survived a while for professional recording applications, but never came close to justifying its early hype.