I cannot multi-task. A friend--was it you, Susan?--told me about someone who cannot read without something on TV to watch at the same time. That's nuts. I am trying to listen to Pandora (right now, the Decemberists are on the Neko Case station; I don't think I'll ever learn to like Mr. Meloy's voice, but I like his songs) and write this at the same time, and can barely do it. Music is not really background to anything that takes up cortex for me. And music is for singing along with, or at least for humming a harmony to. Or escaping inside of.
I can sometimes sign prescription refills while on hold (that's right, being on hold is a task for me, maybe because there is music to sing along with). I can listen to NPR and do dishes. I can sort of drive and drink coffee, although that's iffy. But talk on the phone and check facebook? Give advice and take notes? Sing and blog? Not so much.
Of some comfort is research that shows no one is really good at multi-tasking. Most people just don't know it.