I think a lot of people simply took profits ahead of increased taxes on income and dividends. You can see what insiders are doing here...
There's no way to tell what they are thinking, though, since trades have to be announced.
and this makes as much sense as anything...
With gains of 34% YTD, ~200% over 5-years and ~7000% over 10 years, long term investors in Apple may simply want to cash out this year before the looming tax hikes on long term capital gains. Capital gains, currently at 15% could go as high as 25%. Another factor is the press coverage of the "fiscal cliff" and the confusion it has caused for equity holders. Instead of sitting on the gains, some investors are simply selling now.