Wow. I hadn't seen that before. I had been worried that I didn't address the broader impacts and intellectual merit sufficiently. But now I know why I got the fellowship. My history, research and future plans pretty much all fit into that broader impacts category...
As I understand it, they choose the people to award it to without regard to race or gender. Then they go back and allocate a few additional awards to the top minorities and females not selected already. So that means that depending on how many minorities there are and how many additional awards there are, they could end up going quite far down the list for minorities.
I believe that is really only true within the scientific disciplines. The arts students I know are often not offered any funding at all or are offered funding that is impossible to live on.
I was thinking that this would also mean that there really isn't time to find an adviser that you sync with. I'm waiting on one school, but I think that even if I get this, I will go to one of the schools that I have visited and found potential advisers in.