In any brainstorming session, I can only properly function when I have something to draw on. I feel there's a more productive flow of ideas deas when I'm able to draw certain correlations, flow charts or conceptual ideas. So, I was happy to find out I'm not alone. I just read an interesting article written by Clive Thimpson for Fortune Magazine called "Think Visual - Why the best way to solve complicated problems might be to draw them".
If you're also the type that feels an uncontrolable urge to draw in meetings, worth reading the article.