Email as mind-numbing as pot?
I've long been a fan of the productivity benefits of a quiet, low-interrupt environment. Here's a particularly supportive article about it!
CNN.com - E-mails 'hurt IQ more than pot' - Apr 22, 2005
Other studies show that the time it takes for people to get into their flow state (where they are the most productive) is greater than the average interrupt load.
-Bob