According to The New York Times, they're into blood types. While most Americans know their Social Security numbers and maybe even their cholesterol levels, a strong majority of Japanese know their blood types. That's because in their culture, having Type O or Type A blood says a lot about the kind of person you are.
That might explain why many in Japan are predicting great things for new Boston Red Sox pitcher, Daisuke Matsuzaka, a Type O (listed on Japanese players' trading cards along with height, weight, etc.). The Japanese will tell you that Type O's are typically "warriors," exude self-confidence, ambition, and a strong goal orientation. Those are clearly strong qualities for baseball players, and in other careers. It's noteworthy that Ronald Reagan, among others, was a Type O.
On the other hand, Seattle Mariner Ichiro Suzuki is a Type B - a "hunter," typified by creativity, impulsiveness, and being a free spirit. And in a way, he plays baseball that way, too, always finding new ways to get on base, making the most of his running skills and sliding ability.
So maybe instead of evaluating talent based on their "pipes" or the stations they worked for in the past, we ought to start considering whether there's actually something to this blood type thing. Maybe it could be a predictor of the style and character of a PD or a DJ you're about to hire. If nothing else, maybe it's a great morning show bit or a new opening line that replaces "What's your sign?"