43 Folders has a nice post called Flow: How action and awareness get things done. The post's author shares several snippets about flow. This one is my favorite:
“Flow” is a mental state of deep concentration. It typically takes about 15 minutes of uninterrupted study to get into a state of “flow”, and the constant interruptions and distractions of a typical office environment will force you out of “flow” and make productivity impossible to achieve.
More fuel to the "stop multitasking" argument. Check out all the great info on flow l - lots of links, comments, and trackbacks.