Ellen Ullman, author of the excellent, the Bug on the Evils of Multitasking:

Not that Microsoft is the only culprit; distraction is built into the fabric of today’s electronic world. Icons on the PC toolbar flash; ads on Web pages shimmer and dazzle; software companies send e-mail messages to say your software is out of date; word processors interrupt to correct your spelling; Web pages refuse to show themselves until you update a plug-in; lights on laptops blink at you every time the hard drive whirs into motion (which, I’m here to tell you, happens a lot more often than you would ever care to know). The screens of TV cable news programs make three-ring circuses seem calm. You can’t even enjoy the 10th rerun of your favorite “Law and Order” episode without a glittering promo fluttering at the corner of the screen.