Procter & Gamble Co. VP-Global Business Development Jeff Weedman likes to talk about working on Duncan Hines in the 1970s to illustrate the long reach of P&G influence.

In those days he sat next to future General Electric Chairman CEO Jeffrey Immelt and a bullpen over from Brian Swette, who would become No. 2 to another P&G alum, Meg Whitman, at eBay. He later moved to Crisco, where he reported to Scott Cook, who would go on to found Intuit, and was replaced in his job by Steve Ballmer, who later became CEO of Microsoft.

Just how ubiquitous are P&G-trained marketers? "They're everywhere," said former Global Marketing Officer Jim Stengel, who had just spoken to an audience packed with them to promote his book "Grow" in Mexico City and was on his way to launch it in China, where he expected another gaggle of P&Gers to help form much of the market base there.

Islands of P&Gers are found in unexpected corners of marketing. For example, the chief marketers of the Tampa Bay Devil Rays baseball team (Darcy Raymond) and Tampa Bay Buccaneers football team (Jason Dial) are both P&G alums, but were unaware of this until a reporter brought up the coincidence earlier this year.

Elsewhere in town, another P&G alum, Anne Martin-Vachon, is chief marketing officer of Tampa Bay area's major national media player -- HSN. CEOs of two other area media players -- Catalina Marketing (Jamie Egasti) and Triad Retail Services (Greg Murtagh) -- are also Procter alums.

Increasingly, Proctoids, as they've been known by some, are staffing P&G's competition. CEOs of six major P&G competitors started, and in some cases spent, the majority of their careers there. And unfortunately for P&G, perhaps, some of its most successful CEO progeny work in its own industry, including two people with the fastest-growing top lines in the competitive set: Estee Lauder CEO Fabrizio Freda and Unilever CEO Paul Polman. And for years, P&G was dogged in household care by another successful alum, Bart Becht, who as chairman-CEO of Reckitt Benkiser outperformed P&G on the top line for most of the prior decade.

While its famed alumni are in many ways flattering to P&G, Deutsche Bank analyst Bill Schmitz noted that their career path raises questions about whether P&G has kept its best executives. He singled out Mr. Freda, in particular, who he said wasn't seen as a star at P&G but has produced consistently stellar results at Estee Lauder.

The loss of many top managers to thriving competitors is a consistent complaint among P&G alums, who've seen their stock and options languish in a relatively tight trading range over the past five years.

If losing people to a competitor makes the competition better, "it makes us have to push all the harder," said P&G Global Brand-Building Officer Marc Pritchard. "You're always going to have some who leave who you regret. But it's a really competitive system. Some people make it and some people don't. By and large, it works out the way it should."

Regardless, you could practically populate a marketing-industry association just using P&G alums.

A LinkedIn search finds 100 current CMOs of other companies who started their careers at P&G -- a number greater than Nestle, Unilever and Kraft Foods combined. In all, more than 5,200 former P&Gers are now listed as having marketing duties elsewhere today on LinkedIn, though that remains less than the 7,000 people in marketing, market research, design and PR in P&G's Global Brand-Building Organization.

P&G is well behind the likes of IBM, General Electric and Microsoft in producing alums with CEO titles on LinkedIn, with those companies having heavily stocked talent in a burgeoning number of small tech companies, but it handily beats any other player in its industry.

Doesn't training all those marketers for other people take a toll on P&G?

"The time you invest, you do lose that ," Mr. Pritchard said. "Sometimes it's candidly the right thing for them to go. That's just normal course of business. And even those who go because it wasn't working out for them, and those who go who we wish hadn't left, part of our culture is so strong it's kind of like once you're a P&Ger, you're always a P&Ger, and we just have an affinity with those folks. It's a good benefit, too."

The ubiquity of P&G-trained marketers makes it easier for the company to find partners in media, advertising agencies and for joint ventures, Mr. Pritchard added.

Clorox Co., separated from P&G in a mid-1970s antitrust settlement, has never had a CEO who didn't start his career at P&G. And while the companies compete in many categories, P&G is 20% owner and supplier of technology to Clorox's Glad business.

Perhaps more remarkable is how P&G influence turns up in industries far from its sphere of competition. P&G alum Ed Lonergan recently replaced fellow P&G alum Fernando Aguirre as CEO of Chiquita.

In financial services, the CMOs of both Visa and MasterCard are P&G alums. American Express isn't led by a P&G alum, but CEO Kenneth Chenault sits on P&G's board.

American Express recently partnered with Walmart to bring out Bluebird, an alternative bank card for the unbanked, working with another P&G alum, Eric Hansen, chief marketing officer of Walmart Financial Services. They'll be posing a new challenge for Western Union, where P&G alum Laston Charriez became senior VP-marketing earlier this year.

So how does that P&G influence shape an industry or marketing as a whole?

The salient feature of the P&Gers everywhere, said MasterCard CMO Alfredo Gangotena, "is clearly the power of the left brain -- analysis, logic, construction of the business propositions. Because they're so strong on the left side, it allows them to go to the right-brained side in a more daring way. It's like, if you had a sailboat with a very powerful keel, so you can put as much power in the sails as you want. If you go too strongly on the creative side without the keel, you can flip."

The ubiquity of P&G-trained CEOs often helps spawn hires of more P&G marketers throughout the organization. P&G and Clorox alum Tarang Amin turned to Mr. Stengel for tips on a P&G marketer who would be right for the job before hiring P&G alum Jennifer Steeves-Kiss as CMO.

But not every P&G alum is looking to hire directly out of P&G. Mr. Gangotena echoed the outlook of many executives and recruiters that P&G is different enough from other companies that the first stop of ex-P&Gers isn't always the best. There's no doubt that "Procter plus " candidates are often more sought after than Procter executives, said Heidrick & Struggles recruiter Carlos Cata, himself a P&G alum.

Ex-P&Gers have "a mixed record," said Unilever CEO Paul Polman in an email. He's the classic Procter-plus executive, having become chief financial officer of Nestle, getting passed over for the CEO post, then becoming CEO of Unilever. "In Unilever we are not actively looking for P&G people," he said, "although there are many on the market."

But Mr. Pritchard said P&G's influence on marketing also goes well beyond exporting talent. "We're pretty proud of the influence we have on marketing and brand building in general," he said. "It's been part of our DNA, part of our history. My observation has been, humbly, people do look to P&G and say "How are you doing things?' They took great interest when we started pushing digital hard, when we started pushing branded entertainment."