My favorite example of “incremental innovation” belongs to Dilbert-the cartoon, not the character. Even before the Internet was a gleam in Jeff Bezos’s eye, Scott Adams-Dilbert’s creator-got his syndicate to agree to attach his e-mail address to the strip.

The reason, Adams has explained, was to see what kind of reader feedback-if any-e-mail accessibility might generate. In fact, he still gets much of his best Dilbert material from reader e-mail. “Yes, they send me ideas,” Adams smirked in a Washington Post online discussion. “But the lazy %#$*s refuse to draw the comic too, so I have to do that part.”

Indeed. But the simple act of tagging a comic strip with an e-mail address proved brilliantly innovative. Getting your fans to subsidize your creativity-for free!-is an enviably efficient business model. What Dilbert’s dad did might be called-with apologies to innovation guru Clay Christensen-a “disruptive incremental innovation.”

While technically less innovative than the shifts from, say, piston to jet engines or vacuum tubes to transistors, disruptive incremental innovations have profound effects on business. It’s not about simply extending a brand; it’s about surprisingly cheap, surprisingly easy-to-implement ideas that transform how value is created or perceived. The ideas underlying the successful incremental disruptor almost always seem blindingly obvious in retrospect. Any competitor could have done it.

Apple’s iMac offers a case study in disruptive incrementalism. For all intents and purposes, desktop personal computers were little more than bland beige boxes sold on the basis of features, functionality, and price. The PC industry-IBM, Compaq, HP, Dell, Fujitsu, Hitachi, and so on-publicly considered the outward appearance of their machines to be irrelevant to their customers’ needs and desires. At least, that’s what their research said.

Apple, with its flair for inspiring industrial design but minuscule market share, decided that looks could matter. The resulting iMacs-which offered shockingly little in the way of new features or functionality-represented a triumph in plastic repackaging of an existing product. But they were sold in an intriguing palette of colors-including tangerine(!)-and a Frank Gehry-esque housing that seemed, for want of a better word, cool.

While none of Apple’s competitors or, for that matter, the technical media considered the iMac particularly “innovative,” customers disagreed. They thought color and styling were innovations and said so. The iMac proved a breakout product for Apple and did wonders for both its sales and share price. It also changed marketplace expectations about the visual aesthetics of PCs and other devices.

Innovation cynics might say that what Apple’s Steve Jobs did was tantamount to GM’s Harley Earl slapping fins and chrome grilles on automobiles. But heck! If it sells significantly more cars or more personal computers, then it’s significantly innovative.

The same holds true for James Dyson’s clever idea in 1993 to make the housings of his novel cyclonic vacuum cleaners transparent. Why? Dyson figured that, far from feeling “icky” about seeing their vacuum cleaners filled with dirt and grime, his customers would love to see how well their machines were working. Part of his rationale was that existing suction vacuum cleaners did an inferior job of cleaning-hence no transparent vacuum cleaner bags (even though they would have been easy to produce). While the costs of transparency were minimal, its perceived customer benefits were immense. Customer research affirmed that being able to see how well the Dyson cleaned was a valuable feature. Transparency profoundly differentiated Dyson from its competition-a classic disruptively incremental innovation.

Behind every disruptive incremental innovation, however, is a big idea. For Scott Adams, it was the recognition that readers could be part of his creativity supply chain; for Steve Jobs, that customers might be willing to pay a premium for how a computer looks as well as for how it works; for James Dyson, that letting customers literally see the difference in cleaning quality would make them trust his innovation more and recognize its value.

To be sure, there is a huge difference between radical incremental innovations-innovations that truly are cheap and easy to implement-and radical innovations that look cheap and easy to implement. When Procter and Gamble decided in the 1980s to combine shampoo and conditioner in a single product, for example, the job proved much, er, hairier than the company had anticipated; as it turns out, the two substances have very different chemistries. But the opportunities for disruptive incrementalism seem to be increasing for innovators who believe that even small revolutions can have disproportionately big results.