| daroamer said: Thats not what momentum means. The 360 is selling about 20% MORE this year than last year. The PS3 is selling about 15% LESS than it was last year. PS3 is losing momentum, 360 is gaining momentum. |
Define momentum then. As far as I know momentum actually has no clear cut meaning in business talk, save for "inertia" in some stock value oscillations. And here it does not apply at all.
Why should we refer to YOY instead of latest sales? YOY is very often a poor measure for the success of a product here and now. It goes up when you reach about the anniversary of a particular bad period. The YOY of the 360 will go down after the anniversary of its price cut, and that drop will mean squat about the health of the 360's sales in September 2009.
In general YOY loses much of its predictive value as a marker when there are big factors conditioning the sales that act on about-year-long scales of time (such as a pricecut). It's useful when you contrast it with Month over Month or Week over Week, in recognizing shorter term trends.
