Anne Zelenka at Web Worker Daily had some interesting thoughts about a different mode of productivity that isn't harmed by multitasking. Connected Mode: Multitasking for Productivity:
Conventional wisdom from old-style journalists and not a few bloggers says that multitasking is bad. We need to firewall our attention, prevent interruptions, and work on one thing at a time. But what if this conventional wisdom doesn’t always apply in the new world of work that the web is bringing into being? What if an alternate mode of productivity — connected mode productivity using rapid switching between multiple tasks and maintaining near constant connection with teammates — gives better results for many information manipulation tasks?
The full article (and comments) goes into more detail, particularly emphasizing that we need to be aware of the context of the work in question. Most cases in which I am involved, a focused effort (no multitasking) is going to get things done faster than a divided effort. However, there are times when I am heavily relying on others, and I could imagine the connection being more important than the individual tasks on which we are working.
Still, I don't think I will be advocating multitasking (the task-switching variety) without some serious understanding of the situation.