BARCELONA, Spain — Talk may be cheap, but if Softbank CEO Masayoshi Son has his way, talk-- regardless of distance, length and the number of people in the conversation--will be free "because the mobile phone is becoming an Internet machine."

Son, whose company has turned its Yahoo Japan unit into that nation's dominant Internet search engine, is now providing free, Web-based voice services to its subscribers. "From now on, when we say Internet, we mean mobile handset," said Son. "This is a trend nobody will stop."

Son spoke at the Mobile World Congress here Wednesday (Feb. 13). Fellow panel members shared his belief that "voice will become a commodity very soon" as Internet services become the new frontier for mobile telecommunications carriers. The enthusiasm for this outlook was palpable, as Marco Boerries, head of Yahoo's Connect Life initiative, rattled off a list of e-mail, messaging and social network services being launched by his company. He said, "It's just beautiful. The speed. The power. The graphics!"

Jim Balsillie, co-CEO of Research in Motion (RIM), whose pride and joy is the BlackBerry mobile device, expressed similar excitement about mobile Internet as a business-to-business breakthrough. "This is the Holy Grail," he said. "This is unified communications."

While touting the potential for mobile operators to grow beyond the limits of voice communication, executives shared a common anxiety: that content and service providers will relegate the carriers to a subsidiary role. Balsillie noted, "In all the platform strategies here, does the carrier get enabled or does he get disintermediated?"

Citing Microsoft's rise to dominance over computer industry competitors like IBM, Son warned the same thing could happen to mobile operators who fail to integrate a host of services into their Internet stream. "We have to be careful not to be eaten by the other Internet and service companies."

RIM's Balsillie said one strategy is for carriers to become "a platform for work/life transformation," in which a vast range of Web-based, mobile business services including various e-mail and corporate communications services blend with desktop services and "personalized multimedia". The result may be a stable, "high-ARPU [average revenue per user], low-churn, value-added" customer base, for carriers.

Yahoo's Boerries insisted that mobile operators need not fight with content and service providers for a piece of a relatively limited revenue stream. The reason, he added, is that mobile Internet creates "additional services for [customers]. We focus on creating new revenue, not who gets what from the existing pie. It's all about scale."

Boerries said some of that additional revenue will come from online advertising, which has been an erratic source of income since the Internet grew into a popular medium. Son, on the other hand, expressed relief that the shift of mobile communications from voice to Internet will take pressure off the need to sell advertising. Son noted that Softbank has removed "noisy banner ads" from its mobile Internet service.

"On the small screen, for the sake of consumers, too much advertising is not good," he said. "The advertising-dependent business model for the Internet has to be changed." Son predicted that mobile operators will be able to replace ad revenue with "micropayments," assessed automatically for various services through existing subscriptions.

"Eighty percent of the PC-based Internet depends on advertising. For the mobile Internet, advertising revenue will be about 20 percent," said Son. "People will pay for their data service and for their security. The glory of Google may not last another 20 years."

Boerries disputed Son's figures, insisting that social networking, which involves a younger audience devoted to frequent and lengthy Internet sessions, will remain a vehicle for Internet ads. Balsillie added that revenue from all consumer uses of the mobile Internet will be dwarfed by the more lucrative B2B market, rendering moot the issue of advertising.

If the panel held any reservations about the promise of mobile Internet, it surfaced over the issue of network speed and capacity. Son's success in Japan is based on the widespread integration of high-speed data-packet access throughout most of Softbank's network. HSDPA is unavailable to most carriers outside Japan, although it will be arriving, according to GSM Association CEO Craig Ehrlich, who moderated the panel, faster than anticipated.

Capacity is a greater problem than speed. The wireless "pipe" available for the "rich content" of audio, video and data from the Internet is smaller than the broadband connections that feed fixed-line computers. Said Balsillie, "When you 10x the bit rate, you 10x the system requirements." He warned that every operator who opens its pipe to users who do everything from managing corporate e-mail accounts, streaming video-on-demand and supporting MySpace and Facebook accounts, must have a "data plan." He added, "There's no free lunch in physics."

Son concurred. Without preparation, many operators might see their systems crash around 10 p.m. every night as content overwhelms capacity. "Rich content can't come into the mobile environment," he said, "without manners."