Multitasking in computer human interaction

Meet the Life Hackers from NYTimes

"When Mark crunched the data, a picture of 21st-century office work emerged that was, she says, "far worse than I could ever have imagined." Each employee spent only 11 minutes on any given project before being interrupted and whisked off to do something else. What's more, each 11-minute project was itself fragmented into even shorter three-minute tasks, like answering e-mail messages, reading a Web page or working on a spreadsheet. And each time a worker was distracted from a task, it would take, on average, 25 minutes to return to that task. To perform an office job today, it seems, your attention must skip like a stone across water all day long, touching down only periodically."