Neodegenerate on 23 October 2014
There are 3 answers to this question.
Definition one of "is the system selling well" - Is it profitable for MS?
Definition two of "is the system selling well" - Is it holding onto, or growing, marketshare over the competition and/or its own previous iteration?
Definition three of "is the system selling well" - Is it hitting the general expectations of those who look strictly at sales numbers - without any other indicators?
MS only cares about the top two.
