Thaat is the flavour or inspiration for a song.
There are many claims of tune stealing. As an example "jhooma chooma de de" and "tamma tamma loge". The music directors of these songs claimed that the other copied the tune while his was original. Film magazines spent a lot of paper on this issue during those days.
In my earlier comment in the other blog post I made a claim that Ataullah Khan copied a Rafi saab's song "Ye maana meri jaan" for his "khabar mere marne ki". I was sorry for the comment made. It was more of a friendly hand extended to Ataullah Khan.
I think thaat stealing or thaat inspiration is about friendliness.
What are your views, dear readers !!