** Tig's weekly column fields questions from and for marketers. **
I understand your illustration on above the line vs. below the line offered last week. I'd still like to know the origin of the 'line' itself. Any background you can offer?
In a word: No. I've been frustrated in my attempts to find out the etymology of this phrase. After some extensive research and the pestering of some quite old advertising hands, I haven't found anything credible.