Only a slice of the population qualifies as early adopters of technology just 13.5% according to author Everett Rogers, who coined the phrase. You know the types preordering cutting-edge gizmos before anyone else has heard of them, obsessively scanning industry and product development web sites, comparing notes with fellow geeks and trendsetters on what the next big thing will be.

With Apple (AAPL) taking preorders for the iPad today (and analysts predict Apple will sell between four million and five million units this year), we decided to take a look at the recent history of early adoption.

Conventional wisdom of course is that the early birds get the duds: The gadget might be cool, but in the first generation, the developers haven't gotten the bugs out yet. People are naturally reticent to spend a higher price point on a gadget that will be obsolete in a short space of time, says Luke Flemmer, managing director of Lab49, a strategy and technology consultancy for the financial services industry.

However, demographics might be shifting the dynamics of early adoption. There is a noted generational gap between Millennials (aged 18 to 29) and baby boomers (aged 45 to 63). Half of boomers report never banking via the web, while Millennials, who have been immersed in technology since birth, have come to demand a rich online experience, says Colleen Healy, general manager of U.S. Financial Services at Microsoft. With that demand comes high expectations and perhaps a spike in early adopters who feel advanced tech is more a need than a want.

Here are how early adopters fared with some breakthrough technologies,

and the impact the introductions had on the manufacturers.

Bowmar Instrument Corp.

The so-called Bowmar Brain the 901B had four functions and an eight-digit red LED display and became available in September 1971. It cost $240. As one of the first American-made, handheld pocket calculators (some say it was the first), the Bowmar was an instant success. For a short time, the company dominated the market.

However, just a year later, the Sinclair Executive, another four-function calculator, became available for $90 less, followed by more lower-priced models from Sinclair.

Then Hewlett-Packard (HPQ) and Texas Instruments (TXN) launched the HP-35 and SR-10, the first higher-functioning calculators with scientific and algebraic capabilities, respectively. Later models, like Texas Instruments T1-30 followed shortly after. And prices fell dramatically.

Bowmar filed for bankruptcy protection in 1975 unable to find a business model that suited the rapidly declining calculator prices.

Sony

Years before the iPod, in 1979 the same year that Michael Jackson's "Off the Wall" album was released Sony (SNE)SNE () debuted its first Walkman, the TPS-L2. The cassette-based music device was cumbersome and had little of the functionality that's taken for granted today, but it changed the market for listening devices. Still, Sony stock was little moved by the Walkman's commercial coming out in Japan. Shares fell 12 cents, or 2.7%, the first trading day after the July 1 release and 8.9% in 1979 overall.

Five years later, in the wake of "Thriller," kids could rock out to Jackson with their Discman, or D-50. For something that sparked the race to make music lighter and more user friendly, it did little for shareholders. Sony's stock fell 8.5% in 1984, the year the Discman was released. Over the years, the Walkman has remained an icon. For a trip down memory lane, check out Scott Campbell's take on the Walkman for BBC Magazine, on the 30th anniversary of the device.

International Business Machines

Before IBM (IBM) released this PC on Aug. 12, 1981, it had produced a portable desktop, the IBM 5100. But that suitcase-sized machine cost between $8,975 and $19,975 (depending on memory and add-ons), and wasn't designed for the masses. The IBM PC, instead, cost just $1,565 in IBM Product Centers, and was intended for home use. It was also the first IBM machine composed of off-the-shelf parts and marketed by big retailers like Sears & Roebuck and Computerland. Here's a look at what an original PC looked like. Some four months after the IBM PC's market debut, Time Magazine named the computer The Man of the Year. The machine soon got a huge amount of competition though, and through what is now considered some epic mismanagement, IBM slowly lost PC market share to companies like Apple, Compaq, Hewlett-Packard, Cisco (CSCO), Dell (DELL) and so on.

Apple

Manufactured by Sharp and spearheaded by Apple's then-CEO John Sculley, the Apple Newton was a personal digital assistant (PDA) before anyone knew what one was. Complete with a stylus pen and a touchscreen, the Newton allowed users to manage and share information, and also recognized handwriting and could convert it into typing. The first iteration cost $700, although a later model, the Newton Figaro, with more bells and whistles, cost $6,000. The Newton is now known as a historic failure, says Flemmer, of Lab49. The tech wasn't really up to the challenge. The LCD screen had no backlight, making it hard to read text, a clunky stylus pen, and it never quite caught on. Apple discontinued it in 1998, though techies often refer to the Newton as the iPhone's grandfather.

Palm

This PDA was first made popular by Palm Computing, then part of U.S. Robotics, in March 1996. The Pilot 1000 ($299) and 5000 ($369) were originally called PalmPilots, but had to be renamed after a lawsuit. With backlight control, scroll and application buttons, these early models caught the public's imagination almost immediately.

The company quickly rolled out successive models such as the PalmPilot Personal and PalmPilot Professional in the same price range; for $199, and by 2000, Palm, Inc., then a part of 3Com (COMS), had released the Palm IIIc, its first color-display device, which it touted as the lightest (6.8 ounces), smallest full-function color handheld on the market.

With the Palm IIIc product, customers do not have to trade high-quality color for wearability and long battery life, the company wrote. The Palm IIIc device features a long-lasting (approximately two weeks), memory-free battery that recharges like a cellular phone in its included desktop cradle.

About a week after the debut of the Palm IIIc, 3Com spun Palm (PALM) out into an independent, publicly traded company. The stock fell more than 80% in the first year in the thick of the dot-com bust. Once valued in triple digits, they were recently trading at less than $6 each.

Apple

When the original iPod was unveiled in 2001, it cost $400 for five gigabytes of storage (some 1,000 songs). Unlike some scorned predecessors (see the Newton), it had a white LED backlight and could download 1,000 songs in less than 10 minutes huge for the time. But the price tag still kept it out of reach for a lot of people, plus consumers frequently complained of glitches and frozen screens in the middle of a song. For the past nine years, there have been new iterations every few months: the Nano, the iPod Shuffle, iPod Mini and the iPod Touch. As of January 2010, over 240 million iPods have been sold way more than any of its competitors. And today's iPod costs $249 for 160 gigabytes or 40,000 songs.

Amazon.com

On Nov. 19, 2007, Amazon.com (AMZN) launched its Kindle electronic reader at a price of $399. Investors and consumers guessed that the product, which weighed 10.3 ounces, would make waves. But no one was sure just how big those waves would be.

Though we've already posted the rumours and the news, there's still a lot to know about this mystery disruptor, wrote Wilson Rothman, who was blogging from the live announcement for Gizmodo, the web site devoted to all things gadget-y. The dudes behind me think it might have the most impact on publishing since the Internet, so stay tuned.

By late December 2009, Amazon said its Kindle eBook reader had become the most gifted item in company history. Jefferies analyst Youssef Squali estimated that Amazon had already sold 2.5 to three million units by the end of 2009 from the time of its 2007 launch. Add to that the revenue the company receives from the sale of ebooks and it's clear it was a game changer.

For early adopters, well, it might have paid to wait if they could hold out. On Feb. 23, 2009, a year and three months after the original Kindle launch, the Kindle 2 became available. It had better battery life, faster page-refreshing, was thinner and lighter, and offered more options at a price of $359.