Historically, household robotics have made for fabulous science fiction but miserable business ventures. Even chronically ingenious entrepreneurs like Atari’s Nolan Bushnell and the British innovator James Dyson of vacuum cleaner fame found that their robot ventures did a better job of capturing imaginations than customers. And with the notable exception of Sony’s cute but useless Aibo robo-dog, technology’s giants have all steered clear of the mass-market robot. No “General Robotics” here.

Yet MIT artificial-intelligence guru Rodney Brooks, cofounder of the Asimov-inspired startup iRobot, seems oddly optimistic about the prospect of robotics. His reason? The technology has finally acquired that vital human ingredient that has made a number of similar industries possible: hobbyists and enthusiasts. “Over 20 years ago, people who liked new technologies played with PCs,” says Brooks. “Now they’re playing with robots. The first PCs couldn’t do very much, and neither can the first generation of robots. But they get people interested and excited.”

The same types of students and enthusiasts who once built Heathkits and Altairs-or rebuilt Packards and Nash Ramblers-are taking bots seriously. Bot books, publications, and kits that once sold in the thousands now sell in the tens of thousands. Popular television shows like BattleBots and Junkyard Wars have brought the essence of MIT’s famed Mechanical Engineering 2.70 competition, where students design and build dueling bots, to mainstream awareness. Homebuilt robotics is still more cult than subculture, but its growing popularity is raising a multibillion-dollar business question: will hobbyist/enthusiasts once again be the vanguard of a global industry that matters?

Peel the hagiographic gloss off heroic inventors and you find hobbyists and enthusiasts consistently playing a critical role in the design and diffusion of innovation. So-called home-brew computing made U.S. leadership in personal computing possible. Photography has from its very beginnings been a technology where amateurs exert a greater influence on product development than professionals. The earliest days of radio featured homemade “cats’ whiskers” and germanium crystal receivers. Henry Ford may have started making cars on assembly lines, but automobile innovations have been driven as much by hot-rodders and enthusiasts as industry engineers. Aviation’s origins similarly feature do-it-yourself aerophiles whose passion for airplanes created levels of public awareness and participation that helped launch the industry. The open-source-software movement, under the leadership of Linus Torvalds and Richard Stallman, also reflects a strong hobbyist/enthusiast ethos.

These amateurs enjoy a special niche in the ecology of innovation because they are simultaneously both creators and consumers; they adapt and adopt. They’re not (initially, at least) driven by money; they innovate out of curiosity and pride and necessity. They like to prototype and play. Many of them care far more about cleverness and creativity than the technologies’ original inventors. Indeed, Intel’s former CEO Andy Grove has publicly acknowledged that he completely missed how important personal computing would become and dismissed PC hobbyists as little more than fanatics. In fact, computer enthusiasts not only reframed the market as consumers but provided vital innovation and served as ardent evangelists for the cause.

Of course, there’s a limit to what enthusiasts can accomplish on their own. “Generally speaking, hobbyists are not able to push forward the boundaries of technology,” concedes Dyson. “As soon as any real innovative steps forward are made, the hobby becomes expensive, and hobbyists may have to turn professional to pursue their ideas.”

Still, the essential point remains that innovative firms frequently gain their keenest insights from innovative customers. Those customers often prove to be their most ardent hobbyist/enthusiasts. (Surely, Bill Gates was the most profitable hobbyist Intel could have ever hoped to meet-for better or worse.) This is a phenomenon that companies who are intent on tinker-proofing their products ignore at their peril (see “You Bought It. Who Controls It?”).

Robotics is hardly the only emergent industry that can expect the embrace of the techno-enthusiast. Maybe bathtub biotech will be next to capture the mindshare of the techie tinkerers. Maybe bioinformatics and the diffusion of genetic engineering technologies and techniques will inspire a new generation of bio-hackers. Certainly the technologies are there for those inclined to genetically edit their plants or pets. Maybe a mouse or E. coli genome becomes the next operating system for hobbyists to profitably twiddle. Perhaps this decade will bring a Linus Torvalds or Bill Gates of bio-hackerdom-a hobbyist-turned-entrepreneur who can simultaneously innovate and market his or her DNA-driven ideas.

Management berguru Peter Drucker once remarked that “the purpose of a business is to create a customer.” Clearly, the purpose of an innovative business must be to create an innovative customer. To create innovative customers, however, requires companies to inspire more than a few innovative hobbyists. That’s what Brooks says iRobot is counting on.