It's an axiom of our times that the more technology lets people reach out to the world, the less they want to be reached.
They surf websites without registering. They set up filters to defend their e-mail accounts from spam. Some 64 million households have signed up for the "do not call" registry to keep their home phones from jingling incessantly.
But there's a second axiom of the age: People want to be available, sometimes 'round-the-clock, for certain family members, friends, or even business offers. As companies exploit that desire, individuals will find it hard to keep a low electronic profile, experts say.
The latest proposed intruders:
• The Food and Drug Administration last week approved the use of a tiny chip, about the size of a grain of rice, that could be implanted under the skin to transmit data such as a person's medical history, location, or identity.
• A group of six cellphone companies plans to offer a nationwide directory service for wireless phones sometime next year.
"It's a classic example of a two-edged sword," says Paul Levinson, chairman of the Department of Communication and Media Studies at Fordham University in New York City. "We want to be found by people we want to be in touch with. [And] if Steven Spielberg wants to make a movie of my science fiction novel," says Professor Levinson, who moonlights as a sci-fi author, then "I want to be found 24/7 any place in the world."
Some people we want to hear from only at work; others, only at home.
Mobile phones have muddied these distinctions, adds Levinson, author of "Cellphone: The Story of the World's Most Mobile Medium and How It Transformed Everything!" Once mobile-phone numbers are published in a directory, "the switch has been turned on, so to speak, and there's no way not to be reachable."
Directory assistance calls for wireless phone numbers could bring mobile-phone companies and directory assistance providers $2 billion in additional annual revenue by 2008 through directory fees and more fixed and cellphone minutes used, says Kathleen Pierz, a wireless industry analyst. According to a poll her firm conducted, 53 percent the nation's more than 160 million wireless users might eventually sign up for a directory if customers were convinced it contained sufficient privacy safeguards.
Mobile users can be especially sensitive to unwanted incoming calls because they count as minutes used on their phone plan. But according to market modeling by Ms. Pierz's firm, a wireless directory would result in an average of about only three to five additional calls per phone per year, at an average monthly extra cost of about 45 cents. In addition, she predicts that none of the calls would be from telemarketers, since that practice is illegal under a 1996 law.
As an extra measure of protection, mobile customers already can sign up their phones to the national "do not call" list, which fines violators $11,000 per incident.
The six mobile telecoms are promising to safeguard privacy (Verizon, the largest mobile phone company, with nearly a quarter of the market, has said it will not participate in a wireless directory).
For example, cellphone owners will have to choose to list their phone number, at least in the initial signup; otherwise, it will stay unlisted. Once listed, they can unlist their number at any time at no charge. The companies will not make available any database of phone numbers in print or online. The only way to obtain a number would be by calling 411 and asking, one number at a time.
Customers will also have the option of simply not answering calls from people they don't recognize, says Erin McGee, a spokeswoman for the Cellular Telecommunications and Internet Association, which represents the mobile telecoms.
Meanwhile, the 8 million Americans who have no fixed-line phone will finally have a way to have their wireless number listed in a directory, she says. And on-the-go small-business people, such as plumbers, contractors, and real estate agents, will be easily found by potential customers.
But others are not so sure that all the proper privacy protections are in place. House and Senate committees are considering a "wireless 411 privacy act" to put into law some of the promises the companies are making. Last month, California enacted such a law, which mandates that customers be listed only by choice and can unlist free of charge.
"People have a high expectation of privacy" when they use mobile phones now, says Marc Rotenberg, executive director of the Electronic Privacy Information Center in Washington, who testified on the wireless 411 legislation before Congress. "Part of the success of mobile-phone services has been based on the fact that people have greater control over their telephone numbers than they have with traditional land-line phones."
Parents who give their children cellphones to keep in contact, for example, aren't expecting to get calls from strangers or telemarketers, he says. "There are a whole lot of principles that should kick in when we start collecting personal data" in any digital form, including assurances that it will be used only for the purpose stated, kept secure, and that people have a recourse if there are problems.
"Most consumers don't fully understand the tradeoffs they're making with privacy," adds Pam Dixon, executive director of the World Privacy Forum, a public interest research group in San Diego. Many people are surprised to learn that when they type their home phone number into a Google search box their name and address will probably pop up.
Even when people think they're making an informed decision about their privacy, they often aren't, Ms. Dixon says. Those who use Google's new G-mail, for example, may be willing to trade a free e-mail account for letting Google scan their messages and present ads that relate to them. But what about the people who send e-mail to the G-mail account? They may not have given such consent.
The potential widespread use of the VeriChip, a tiny radio transmitter stuffed under the skin, is "a nightmare situation" for privacy, Dixon adds. At first, people might be induced to wear the devices through incentives or in order to work at certain jobs, such as in high-security areas. But before long, the transmitters could be broadly required.
"All of a sudden it becomes mandatory for certain classes of people," she says. "I just see this as an extremely slippery slope."