They had the world at their fingertips, but still wound up at the wrong place. The two women were so mesmerized by their smartphones that when the elevator they were riding opened up, they just walked out. Neither one realized the mistake — or the other's presence — until the doors shut and they looked up from their screens.

Absorbed in distant dialogue, both women lost track of the here and now.

"I don't think either of us noticed the other person," says Kai Brown, a 32-year-old real-estate woman from Kane'ohe. "It wasn't until she said something that I realized she was even there. She said, 'What would we do without our phones?' I said, 'Probably talk to each other.' "

Smartphones, such as iPhones, Treos and Blackberrys, link people as never before. With them, users can access their e-mail, surf the Web, send texts, take photographs, listen to music and yes, even call someone. Millions of messages tug at attention spans every day.

But the side effect is this: People can be so addicted to their tiny screens and keyboards that they often barely notice what's going on around them. The digital world has a term for it: continuous partial attention.

The phenomenon shows no sign of letting up. Mobile phone use, including the multitasking BlackBerries and iPhones, among the most ubiquitous models, continues to grow just about everywhere.

EAGER LEGION OF USERS

The Federal Communications Commission reported in February that there were 241.8 million subscribers in the United States in 2006. It also tracked text messages, which reached an all-time peak in December 2006, when 18.7 billion messages were exchanged.

In Hawai'i, the FCC found an eager legion of users: Slightly more than 1 million subscribers in a population of 1.2 million people.

The proliferation of these personal communication devices are changing the way people relate to each other. In practically every social setting, from the classroom to the dinner table, they have the power to intrude as often as fingers can tap.

Jen Ozawa, a mother of three young children who says she's "guilty of texting and browsing the Web in public," has often seen the peculiar communication breakdown that the devices create.

"I find people don't have a sense of people right in front of them," she says. "You are more tempted to sit and text someone than carry on a polite conversation with the person in front of you."

That behavior is part of the motivation that has kept Cheryll Aldridge from using her iPhone to text friends. An information technology specialist at Kapi'olani Community College, Aldridge uses the phone to communicate, often by e-mail, with her husband, who has his own iPhone. Her goal is to prevent technology from creating bad manners, but she admits occasionally crossing the line.

"I do use my phone as an excuse not to have a conversation," she says. "Say I am in an elevator or at a bus stop, it's like being on the phone and not having to communicate with people around me. I appear busy."

SOCIAL EXPECTATIONS

David Lassner, vice president for information technology at the University of Hawai'i, says his iPhone, like the Blackberry he had before it, is an important tool. But don't blame the technology, he says.

"It is a matter of personal discipline to not let it be intrusive," he says.

Sometimes the smartphones, like laptops, can siphon away attention from an important classroom discussion or meeting, Lassner says. At other times, the devices link their users with valuable information that a user needs immediately. A puzzled student can find information about something that was said only a moment before in a lecture, he says.

"That opportunity is really huge — again, if people manage it well," he says.

Lassner has his limits, though. He says he finds it annoying when people hold a smartphone in their lap at dinner "as if no one else can see that."

"I think we are at a time where social expectations are changing," he says. "Is that right or is that wrong? I don't know. It has to do with the expectations of the people at the time. If you are at the table and someone does that, do you think it is rude? I think that is part of what is happening in society at large."

Most likely, Lassner wouldn't enjoy a meal with L.P. "Neenz" Faleafine, a 37-year-old Web site editor.

At nearly every juncture in her day, Faleafine's fingers are dancing on her mobile phone keypad in an effort to communicate what she's doing to a circle of subscribers. She uses a pair of social networking services — Twitter and Britekite — that allow her to send out one- or two-sentence statements and photos. When she's at a restaurant, she'll send out a message that she's arrived, then take a photo of her meal and beams that out as well. More than 1,000 people are on the receiving end of her updates.

Her two children, ages 4 and 12, are so accustomed to this behavior that they often bemoan missed opportunities to take a photo of something.

"It cracks me up that they know," Faleafine says.

Knowing what your friends and co-workers will consider rude is the key to knowing whether it's acceptable to focus more on your smartphone than your surroundings, she finds. For example, Faleafine turns off her phone when she's visiting her mother or when she's in a meeting.

"You have to know your audience," she says. "It all depends on who you are with. If you have any inclination that someone is uncomfortable, don't do it or ask permission."

Any exceptions? Computer afficionados like herself.

"If I am with the local geek community, and we are at a meeting, and there is a speaker up there, and half the audience is looking at their cell phones or iPhones, I presume they are talking to the rest of the world and letting them know what the speaker is saying," she says. "I don't think they would think that was rude. Even if I was the speaker, I would feel a little bit honored."

'ALWAYS IN TOUCH'

It's unlikely that this will be an issue for the next generation. Instant communication is the norm, so don't take it personally, advises 30-year-old Jonathan Wong, who investigates new technology for possible classroom uses at Honolulu Community College.

"One of the trends of the younger generation is the whole social networking thing," he says. "You are always in touch with your friends. It's how the culture of young people is evolving these days. A text message to them is like an e-mail was to us about 10 years ago."

Wong, who is also a graduate student in business administration, uses his phone to take notes and has found himself on the receiving end of withering glares from teachers and colleagues. They usually fall silent when he shows them what he's doing.

"There is a generational disconnect for some who don't understand the technology," he says. "Kids are multitaskers. They can be taking notes and can be having a conversation."

Unfettered access to each other has created a greater sense of urgency in the digital community. Just ask Brown, the Kane-'ohe real-estate woman who says her iPhone changed her life.

She loves the fact that she can be anywhere and turn to her phone for help. But there's a downside that has nothing to do with elevator doors.

"Professionally, people have an expectation that they can get a hold of you at any time," she says. "So if you don't respond in an hour or two, they call you up and say, what's the holdup?"

It's a thought that makes her laugh out loud.

"You have fewer ways to escape."