Presumably, abandoning the practice of scheduling heavy "banks" of flights at certain peak points of the day in favor of a more constant number of movements per hour. This irons out the peaks and slack times inherent in bank hubbing.

Pros: less chance of congestion delays; shorter taxi times; fewer waits for occupied gates to free up. Cons: longer layover times; maybe fewer seats departing at high-demand periods like dinnertime.

I am all for them trying it out at MEM to see if it helps things any, though with the reduced schedule this year I haven't had any real delays in/out of DTW/MSP.