NEW YORK (Fortune) -- People are becoming increasingly dependent on their cellphones. According to Dan Schulman, CEO of cell operator Virgin Mobile, one in five will interrupt sex to answer their phone.

That was just one surprising insight from an intense 25-person seminar on "The Mobile Generation" at the Aspen Institute in August, with Schulman and other top thinkers.

Much of the discussion focused on how quickly young people worldwide are migrating to mobile communications and integrating them into their lives.

"People leave a movie and text each other, and then text each other again before they go to sleep," said Jerry Murdock, a venture capitalist with Insight Venture Partners. "This is something new - maintaining an ongoing dialogue with someone wherever you are." He says we are entering an era of what he calls "co-presence."

"I know a 32-year-old whose boyfriend used SMS to break up with her," recounted John Seely Brown, the emeritus director of Xerox PARC. Responded the other Brown in the room - Shona (no relation) - who is senior vice president for business operations at Google (Charts): "For the record, that's tacky."

There was much discussion about mobile applications of the future. For instance, said Shona Brown: "Someone will pay for pizza with a cellphone, and their friend will use [phone-to-phone] infrared to top off the others' stored value card."

Esther Dyson, the Internet investor, pundit and author, talked about how great are the opportunities for mobile applications that "foster interaction among people." She added "These devices are present almost all the time. They become almost part of you."

But Dyson is not sanguine about the societal implications of all this. Said she: "I worry about something I call Mental Diabetes Type 2 - a lack of ability to think deeply and in a concentrated fashion over a period of time. We're getting a diet of empty information calories that's over-processed, over-sugared, too bite-sized and way too appealing."

Added Dipchand Nishar, who oversees Google's wireless efforts: "We had Generation X and Generation Y. Now we have Generation ADD."

Others - notably Murdock and Schulman - were less worried, saying that mobile phones and computers were leading kids to have more friends and more social interaction, which probably is a good thing.

The notion that the mobile phone or its heirs will eventually replace the PC was roundly rejected by many of those present. "That's a myth," said Nishar. He said that the average use of a phone today is about 4 minutes, whereas the average PC data session is around two hours.

Much discussion was devoted to how wireless mobility is changing advertising. Schulman said that Virgin Mobile enables its customers - mostly young people - to opt in to watch commercials in exchange for free minutes. "We've been shocked at how many signed up," he said. "For them it's just entertainment." Advertisers participating in the program include Pepsi and Xbox.

Despite the fact that more than two billion people worldwide already have cellphones, everyone agreed the growth opportunities are massive. "Most people are still not connected," said Padmasree Warrior, CTO of Motorola (Charts).

The design challenges to reach the unconnected are great, she said. "The next billion are in China and India and places like that. And many of them can't type or even read."

But Mircea Dan Geoana, the chairman of the foreign relations committee of the Romanian Senate, said that in his relatively poor country of 22 million there are already 10 million mobile phone subscribers.

Kamal Qadir is CEO of CellBazaar, a Bangladeshi company which operates an online Craigslist-like buying-and-selling service that rural businesspeople access exclusively over mobile phones. His company charges nothing for the service, making its money by sharing the revenues that cell carrier Grameen Telecom, the country's largest, gets from carrying the calls.

Said he: "One study showed that more than 40 percent of rural cellphone use in Asia is for business." It was the kind of expectation-confounding comment that characterized the entire three days.

With wireless users growing rapidly and many cellphones built with processing power comparable to 1998 PCs, this crowd presumes that mobile connectivity will continue to dramatically change all our lives.