There's been a discussion about belt progression in jiu jitsu over at the Jiu Jitsu Gear Forum the past few days.
My favorite article on the topic remains this one from Roy Harris, though there are a number of good ones out there.
Recently I thought up this shorthand, which I think sums things up well.
White belts have heard what they are supposed to do.
Blue belts know what they are supposed to do.
Purple belts do what they are supposed to do.
Brown belts do what they are supposed to do very well.
Black belts do what they are supposed to do very well on a consistent basis.
