Fans maintain the benefits outweigh the drawbacks. Knowing when others are available can generate unexpected paybacks, says Greg Vigil, director of the PowerGrip unit at Gates Corp., a Denver maker of automotive and industrial rubber belts and hoses. During a product-development meeting in Scotland last January, Vigil saw in the corner of his laptop screen that the company's technical director for Asia, Guenther Heinz, had become available via instant message and asked if he would join the meeting.

It was late in the evening in Tokyo, but Heinz agreed to join the discussion by telephone, outlining products and technologies his team was developing in Asia, Vigil says. That spurred ideas for products in Europe and North America. Following up on the chance interaction, Vigil will soon travel to Japan and China to meet Heinz and talk further.

Artists at San Francisco-based Industrial Light & Magic, a division of Lucasfilm Ltd., used to crowd a screening room for up to two hours each morning to review the prior day's work. Now, supervisors feed suggestions to the artists over a custom-built instant-messaging system in which each participant can see others' comments. "Artists are able to get feedback more quickly and continue to work" without leaving their desks, says visual-effects supervisor Tim Alexander, whose latest work includes "Harry Potter and the Order of the Phoenix."

At Adecco, Baruch says instant messaging gave him an edge in a recent meeting with an unhappy client. While the client was in the room, Baruch sent instant messages to colleagues to assemble data showing Adecco had upheld its end of a contract. "It added an important dimension to how we operate," he says.

Last year, Baruch used instant messaging to coach Wendy Liberko, a vice president who reports to him, through a sensitive meeting with a poorly performing employee. Baruch, Liberko and the employee were in three different locations, joined by a telephone conference call.

"He would send me messages saying, 'Good question!' or 'Don't forget to bring up those figures,"' Liberko says. She says she now uses the same tactics in Internet conferences with her nationally dispersed staff.

Liberko also says that instant messaging has reordered her communication priorities. She now deals with messages first, followed by voice mails, and finally e-mail. At 11 a.m. one recent day, she had 150 unread e-mail messages, she said, and no intention of "even glancing at" them before the day's end.