It's actually down on the trend line. Your numbers average out to 6,576 per quarter, so lower than the first q. So while there was an uptick it was because of delayed demand (ie, people knew a new macbook was coming out). Looking at the number it looks like the new macbooks have actually hurt their sales.

People where just hungry (read: starving) for any kind of update. That's why.

Agreed, sentiment can be down with sales still going strong. I suspect had Microsoft been able to produce something and strongly market it in Dec/Jan the numbers might be a little different.

There's "pent up demand" because people were waiting for the MBP and bought it, and didn't buy any PC.