Ok, here's an experiment in concentration. Start a blog post. Now plug in something like your ipod into your ears. Turn it on to something that's like talk radio (like a podcast). Try and listen the podcast and blog at the same time. Come back two or more days later and see what sort of blog entries do you make.
So far I've noticed that I've written things like "it seamed like an important result" or "rankin is important". I really do thing it's true that there are parts of our brain that can't really multitask out. Language centers are something that are devoted to one stream at a time and doing two language tasks are the same time (constructing speech and understanding it) is something that makes a person blog less impressively and still not really understand what was spoken to him.
Think of it as the "Hey Honey" effect. Every husband has encountered this. The wife can be telling you about her day and you are reading the paper and when a question is posed you go "Huh?" to one of them. And we all know which one had the priority.....
And we know who is the dog house now. Maybe some meditation can mitigate this or if you kept listening to podcasts and blogged you'd learn to mitigate the symptoms slightly.