Feeding the terminals remains the heart of the business plan. Matt Winkler, the founding editor of Bloomberg News, said that Bloomberg’s moves into the consumer space all “increase the awareness of the value of Bloomberg.” That awareness, in turn, strengthens the company’s core terminal business in two ways. It helps Bloomberg reporters get better access to sources, he says, because as sources become more likely to talk to Bloomberg “the Bloomberg terminal becomes more valuable.” Winkler cites a February interview with President Obama—conducted by Bloomberg News veterans Albert Hunt, Julianna Goldman, and Michael Tackett, as well as recently hired Bloomberg Businessweek editor Josh Tyrangiel, and unrolled across the company’s public Web sites and Bloomberg Businessweek—as an example of the access the company’s consumer presence hopes to deliver.

Second, the exposure helps sell terminals. Winkler’s current favorite illustration is a retired broker named Michael Robbins, who had let his terminal subscription lapse. Robbins so enjoyed a March review—on the free Web site—of the Metropolitan Opera’s production of Ambroise Thomas’s Hamlet, written by arts and leisure editor Manuela Hoelterhoff, that he told me it “was a major catalyst” in his decision to ask his former partners, for whom he is consulting, to renew his subscription.

The Thomson Reuters’ model is similar—in fact, the company has been striking a balance between professional and consumer news since its inception nearly a century and a half ago. “At 100,000 feet, the two companies are doing exactly the same thing,” said Devin Wenig, ceo of the Thomson Reuters markets division (and my boss’s boss). “We have a core news engine that exists for one purpose, and that is to help our clients make money.” News supports all of the market division’s business, but just $365 million of the unit’s $7.5 billion in revenue in 2009 came directly from its traditional media and consumer operations (mostly from syndication and its public Web site).

But like Winkler, Wenig thinks a strong consumer presence has helped that core professional business by winning over sources: “It helps us to get access to people that matter.” More consumer visibility appeals to reporters, too. “It helps us hire good people,” Wenig said, citing Jim Impoco, a former New York Times editor who leads enterprise reporting for Reuters in New York.

Edging into the consumer market is appealing for these two private-content firms for one other reason: since they already have the manpower, it is cheap, particularly relative to the cost of business for the legacy players. “If you look at the mastheads of Bloomberg Businessweek and Bloomberg Markets, there aren’t a lot of people there,” Winkler notes. But since the magazines are an extension of Bloomberg News, “the reporters in our 148 bureaus around the world” can contribute.

Wenig agreed: “The marginal cost of putting our content into a consumer environment is almost zero. I wouldn’t be running a 2,800-person news organization just to build a consumer product, but that is the organization I have.”

For mass news organizations, the big question is how much news they can pull back behind an online veil. Reuters and Bloomberg grapple with the opposite issue—how much ankle they can expose to a mass audience without reducing the value of the information they offer to their high-paying, private client base. “There are constant discussions about it,” Winkler said. “You have to give people just enough so they appreciate what you’ve done, but not so much that it could in any way replicate a Bloomberg. You put enough scoops in front of people to say, ‘That’s a great Web site.’ But you don’t give them every scoop. The time delays are a part of it.”

Chrystia Freeland , the former U.S. managing editor for the Financial Times, is global editor-at-large for Thomson Reuters.