Improve effectiveness and do NOT multi-task!

Research just published in the Proceedings of the National academy of Sciences of the USA suggests that ".. heavy ..multitaskers are more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory. This led to the surprising result that heavy multitaskers performed worse on a test of task-switching ability, likely due to reduced ability to filter out interference from the irrelevant task set. These results demonstrate that multitasking, a rapidly growing societal trend, is associated with a distinct approach to fundamental information processing.
http://www.pnas.org/content/early/2009/08/21/0903620106.abstract

So in short the study found that multitaskers were actually quite ineffective at managing information, maintaining attention, and getting results. Staying focused on some tasks and especially on the outcomes of the few tasks you are involved in, helps you to filter out non essential information and not lose precious energy by switching from one to another task constantly.