Multitasking and Productivity
Something I read a few years ago led me to go on a quest to reduce the number of things I attempt to do simultaneously. If I need to concentrate, I close my email, shut down my IM clients, and focus on the task at hand because there's a fair amount of science indicating people waste more time when they try to do too many things at once. How much multitasking is too much varies from person to person, but it creates a struggle for priority in your brain that often leads to wasted time figuring out where you are in each task. I can't find the original article I read about the negative impact of multitasking, but this highlighted article from Scribd does a good job of pointing out how the brain works (or doesn't). The relevant section starts on Page 4, but the whole article is fairly interesting.
The Multitasking Generation - Multitasking in the Digital Age (Highlighted)