Someone on CNET posted this:
We've worked it out on the KitKat Google+ page.
3 days ago they posted something about Roger Moores birthday and a 007 image but only the 7 was made of KitKats then 2 days ago they posted 'Everybody dance now' but the image was of the Android KitKat dancing made up of 6 KitKat bars.
Yesterday they posted an image saying 'THIS IS IT' made up entirely of KitKats. The caption is 'Sometimes you have to look for the signs…' and the 'S' in the image looks like '5'. Then finally today they showed an image of a standard 4 finger KitKat and 4.4 next to it.
What we are seeing is a countdown; 7, 6, 5 and 4. This means presumably tomorrow Nestlé/KitKat will post something relating to '3' and that will confirm it. So the main date to look out for now is Monday 21st October OR Tuesday 22nd October depending on how their countdown works.