The Blackberry, a portable phone that also receives e-mails, is taking over the lives of many American executives and not always for the better.
Donald Caron, a senior vice president for Smith Barney Citigroup, has not turned his Blackberry off for more than a year. Bethany Ingwalson, lawyer for the Internal Revenue Service, dumped a boyfriend who became addicted to his machine.
Canadian firm Research In Motion (RIM), which launched the Blackberry in 1999, announced Wednesday that it now has two million subscribers around the world and the figure has doubled in the past 10 months.
For Caron, an investment specialist, the Blackberry has become an indispensable part of his life, even if his family may not like it.
"People may not be able to get you on your cell phone when you are in a meeting but they can with a quick question by e-mail."
Caron said his wife thinks it is more intrusive than he does but the executive believes it avoids future problems.
"In the service business, if you get an e-mail at 10 o'clock at night, it happens to be because it's when it's convenient for them, and it's usually a quick note."
"If you are playing golf, sometimes you'd prefer to turn the thing off and not know about it to completely get away. I keep it on."
The last time he did not have it activated was when he went skiing.
Ingwalson, a lawyer for the US tax service, said the obsession of her former boyfriend Bill for the Blackberry was the straw that broke the camel's back.
Bill, according to Ingwalson, was "completely neurotic" about the machine, even disappearing to a restaurant bathroom to check his e-mails.
"At the airport in Washington on our way to Mexico and he was stuck on it. Then connecting in Miami, he was on his Blackberry again, frantically writing e-mails because he was afraid he would not have coverage in Mexico.
Just a little bigger than a normal mobile phone, the Blackberry has a keyboard enabling users to type messages.
RIM's machine dominates the market because it is the most simple to use.
At the start it could only receive messages, but the addition of the telephone services dramatically increased its appeal. Some executives have become so hooked that it is now known by some as the "crackberry" in a veiled reference to the addictive drug crack.
About 15 percent of staff at Smith Barney, the brokerage subsidiary of Citigroup, have Blackberries linking them to their office computers wherever they go, according to Caron.
Steve Taft, the Washington-based vice president and portfolio manager for another major US investment bank, is resisting the trend, however.
"It is very intrusive. I could be sitting with people for lunch and they are checking their e-mails. It breaks down the walls for your personal space."
Taft says he can see the benefit of the speed and convenience.
"But I would never want one, I don't want to be accessible all the time. I have a friend who even checks his messages on the golf course," he said.