But, all have different view point over this "Line" and its representation ... and so do I.
The "Line" as per me is the Line beyond which you can personaly interact with your TG.
ATL do not cross this line. BTL always work beyond this line. TTL always cross the Line in a mid way.
Yes, this is a Line beyond which promises made in ATL do not work; here with BTL you have to actually make those promises (made about the product, whether it is about Positioning, Quality, Feature etc.) come true.