Who is Going to Pay for Those 18 Minutes?

NYT article on the perils of multitasking.  The money quote:

In a recent study, a group of Microsoft workers took, on average, 15 minutes to return to serious mental tasks, like writing reports or computer code, after responding to incoming e-mail or instant messages. They strayed off to reply to other messages or browse news, sports or entertainment Web sites.

There are some other good studies mentioned in the article.  Worth a read -- if you've got the time.