For the first half-hour of the meeting, it was hardly surprising to see a potential client fiddling with his iPhone, said Rowland Hobbs, the chief executive of a marketing firm in Manhattan.

At an hour, it seemed a bit much. And after an hour and a half, Mr. Hobbs and his colleagues wondered what the man could possibly be doing with his phone for the length of a summer blockbuster.

Someone peeked over his shoulder. "He was playing a racing game,” Mr. Hobbs said. "He did ask questions, though, peering occasionally over his iPhone.”

But, Mr. Hobbs added, "we didn’t say anything. We still wanted the business.”

As Web-enabled smartphones have become standard on the belts and in the totes of executives, people in meetings are increasingly caving in to temptation to check e-mail, Facebook, Twitter, even (shhh!) ESPN.com.

But a spirited debate about etiquette has broken out. Traditionalists say the use of BlackBerrys and iPhones in meetings is as gauche as ordering out for pizza.

Techno-evangelists insist that to ignore real-time text messages in a need-it-yesterday world is to invite peril.

In Hollywood, both the Creative Artists Agency and United Talent Agency ban BlackBerry use at meetings. Tom Golisano, a billionaire and power broker in New York State politics, said last week that he pushed to remove Malcolm A. Smith as the State Senate majority leader after the senator met with him on budget matters in April and spent the time reading e-mail on his BlackBerry.

The phone use has become routine in the corporate and political worlds — and grating to many. A third of more than 5,300 workers polled in May by Yahoo HotJobs, a career research and job listings Web site, said they frequently checked e-mail in meetings. Nearly 20 percent said they had been castigated for poor manners regarding wireless devices.

Despite resistance, the etiquette debate seems to be tilting in the favor of smartphone use, many executives said. Managing directors do it. Summer associates do it. It spans gender and generation, private and public sectors.

A few years ago, only "the investment banker types” would use BlackBerrys in meetings, said Frank Kneller, the chief executive of a company in Elk Grove Village, Ill., that makes water-treatment systems. "Now it’s everybody.” He said that if he spotted 6 of 10 colleagues tapping away, he knew he had to speed up his presentation.

It is routine for Washington officials to bow heads silently around a conference table — not praying — while others are speaking, said Philippe Reines, a senior adviser to Secretary of State Hillary Rodham Clinton.

Although BlackBerrys are banned in certain areas of the State Department headquarters for security reasons, their use is epidemic where they are allowed.

"You’ll have half the participants BlackBerrying each other as a submeeting, with a running commentary on the primary meeting,” Mr. Reines said. "BlackBerrys have become like cartoon thought bubbles.”

Some professionals admitted that they occasionally sent mocking commentary about the proceedings, but most insisted that they used smartphones for legitimate reasons: responding to deadline requests, plumbing the Web for data to illuminate an issue under discussion or simply taking notes.

Still, the practice retains the potential to annoy. Joel I. Klein, the New York City schools chancellor, has gained such a reputation for checking his BlackBerry during public meetings that some parents joke that they might as well send him an e-mail message.

Few companies have formal policies about smartphone use in meetings, according to Nancy Flynn, the executive director of the ePolicy Institute, a consulting group in Columbus, Ohio. Ms. Flynn tells clients to encourage employees to turn off all devices.

"People mistakenly think that tapping is not as distracting as talking,” she said. "In fact, it can be every bit as much if not more distracting. And it’s pretty insulting to the speaker.”

Still, business can be won or lost, executives say, depending on how responsive you are to an e-mail message. "Clients assume they can get you anytime, anywhere,” said David Brotherton, a media consultant in Seattle. "Consultants who aren’t readily available 24/7 tend to languish.”

Playful electronic bantering can stimulate creativity in meetings, in the view of Josh Rabinowitz, the director of music at Grey Group in New York, an advertising agency. In pitch meetings, Mr. Rabinowitz said, he often traded messages on his Palm Treo — jokes, ideas, questions — with colleagues, "things that you might not say out loud.”

The chatter tends to loosen the proceedings. "It just seems to add to the productive energy,” he said.

But business relationships can be jeopardized. Lori Levine, the founder of Flying Television, a talent-booking agency in Manhattan, said that in an effort to be environmentally sensitive she instructed employees to take notes on BlackBerrys instead of paper during client meetings.

"Then I got a call from a client screaming that our vice president spent an hour on his BlackBerry during a huge meeting,” Ms. Levine recalled. To soothe the client, Ms. Levine read aloud the notes the vice president had taken.

In Dallas, a college student sunk his chance to have an internship at a hedge fund last summer when he pulled out a BlackBerry to look up a fact to help him make a point during his interview, then lingered — momentarily, but perceptibly — to check a text message a friend had sent, said Trevor Hanger, the head of equity trading at the hedge fund, who was helping conduct the interview.

Very few companies have policies on smartphone use in meetings, which leaves it up to employees to feel their way across uncertain terrain.

To Jason Chan, a digital-strategy consultant in Manhattan, different rules apply for in-house meetings (where checking BlackBerrys seems an expression of informal collegiality) and those with clients, where the habit is likely to offend. There is safety in numbers, he added in an e-mail message: "The acceptability of checking devices is proportional to the number of people attending the meeting. The more people there are, the less noticeable your typing will be.”

Beyond practical considerations, there is also the issue of image. In many professional circles, where connections are power, making a show of reaching out to those connections even as co-workers are presenting a spreadsheet presentation seems to have become a kind of workplace boast.

Mr. Brotherton, the consultant, wrote in an e-mail message that it was customary now for professionals to lay BlackBerrys or iPhones on a conference table before a meeting — like gunfighters placing their Colt revolvers on the card tables in a saloon.

"It’s a not-so-subtle way of signaling ‘I’m connected. I’m busy. I’m important. And if this meeting doesn’t hold my interest, I’ve got 10 other things I can do instead.’ ”

The New York Times