THIS is Charles Lax's brain on speed.

Mr. Lax, a 44-year-old venture capitalist, is sitting in a conference for telecommunications executives at a hotel near Los Angeles, but he is not all here. Out of one ear, he listens to a live presentation about cable television technology; simultaneously, he surfs the Net on a laptop with a wireless connection, while occasionally checking his mobile device -- part phone, part pager and part Internet gadget -- for e-mail.

Mr. Lax flew from Boston and paid $2,000 to attend the conference, called Vortex. But he cannot unwire himself long enough to give the presenters his complete focus. If he did, he would face a fate worse than lack of productivity: he would become bored.

''It's hard to concentrate on one thing,'' he said, adding: ''I think I have a condition.''

The ubiquity of technology in the lives of executives, other businesspeople and consumers has created a subculture of the Always On -- and a brewing tension between productivity and freneticism. For all the efficiency gains that it seemingly provides, the constant stream of data can interrupt not just dinner and family time, but also meetings and creative time, and it can prove very tough to turn off.

Some people who are persistently wired say it is not uncommon for them to be sitting in a meeting and using a hand-held device to exchange instant messages surreptitiously -- with someone in the same meeting. Others may be sitting at a desk and engaging in conversation on two phones, one at each ear. At social events, or in the grandstand at their children's soccer games, they read news feeds on mobile devices instead of chatting with actual human beings.