In Oh, Sweet Revenge, an oldish Newsweek article, Dunkin’ Donuts’ chief Jon Luther says his company is helped by its rivalry with Starbucks: “[It’s] created an awareness for the category, and we’re benefiting.”

The chain’s success illustrates a little-advertised truth of business. Too often the financial pages read like the sports section, filled with winners and losers. Reality is more complex. In many markets, business is not a zero-sum game, and competitors create opportunities.

The article includes some lessons on playing “business defense”...

Markets Have More Niches Than You Think: Dunkin’ Donuts, Starbucks and Krispy Kreme all sell pastries and caffeinated beverages, so they’re obvious competitors. But beneath that similarity, they’re serving different markets. Krispy Kreme’s customers visit only occasionally but buy dozens of donuts; that chain is peddling a dietary splurge, not daily sustenance…Starbucks chief Howard Schultz has always seen his stores as neighborhood hangouts, a sort of nonalcoholic “Cheers” setting with comfy chairs, porcelain cups and, increasingly, wireless Internet access. Dunkin’ Donuts, in contrast, is increasingly built on speed. Most of its new stores feature drive-throughs, and the chain bills itself as a pit stop for harried commuters…

Grow at Your Own Speed: If Starbucks seems ubiquitous, that’s because national expansion was part of Schultz’s game plan when he began reinventing the coffeehouse in the mid-1980s. But that fast-growth strategy caused growing pains early on. Dunkin’ Donuts, by contrast, is still concentrated on the East Coast; it has just a few dozen locations west of the Mississippi. Instead of conquering new lands, Dunkin’s managers have spent much of their energy exploring how deeply the brand could penetrate existing markets. The result: in Massachusetts, where the quickest way to get someone lost is to give directions that include the phrase “Turn left at Dunkin’ Donuts,” there’s one store for every 7,389 residents, compared with one Starbucks for every 15,383 in its home state of Washington.