Multitasking may be harmful?

I'm a serious multitasker - I have to be to be able to get things done but yet the title linked CNN article claims that those who multitask did worse on attention tests than those who don't. Frankly I find that hard to believe, having survived raising five children along with having a life that guarantees one never knows what the meaning of bored is, it's a skill. One that perhaps everyone doesn't have but nonetheless? If I didn't multitask, it would take more hours than the day has to get things done.