When one of the most important e-mail messages of his life landed in his in-box a few years ago, Kord Campbell overlooked it.
Not just for a day or two, but 12 days. He finally saw it while sifting through old messages: a big company wanted to buy his Internet start-up.
"I stood up from my desk and said, ‘Oh my God, oh my God, oh my God,' " Mr. Campbell said. "It's kind of hard to miss an e-mail like that, but I did."
The message had slipped by him amid an electronic flood: two computer screens alive with e-mail, instant messages, online chats, a Web browser and the computer code he was writing.
Read more: Hooked on Gadgets, and Paying a Mental Price