According to this New York Times article, doing more than one thing at a time may cause some problems, delays, and possible errors. And, contrary to popular opinion, younger folks are no better at multitasking than us oldies are.
I have to admit to being an unabashed multitasker at most times (I have to get far, far away from my computer when on conference calls; otherwise, I will definitely not be able to give those on the phone my full attention). When it comes to writing, though, I need to mute my answering machine, ignore e-mail, and put everything I have on that one task. But for everything else, I usually end up doing at least two things at once.
The research in the NYT article says multitasking can result in a delay of up to a second on one of the tasks, which could be a big deal if you're driving and talking on your cellphone, but not so much if you're answering e-mail while on the phone. Still, when dealing with humans either on the phone or electronically, they deserve full attention. I'm going to do my best to give it to them from now on. Except maybe the PR people who call to ask me if I got their press release, then go on to read it out loud to me over the phone...