> Below the line (BTL) advertising is more one to one, and involves the distribution of pamphlets, handbills, stickers, promotions, brochures placed at point of sale, on the roads through banners and placards. It could also involve product demos and samplings at busy places like malls and market places or residential complexes.
http://www.theadvertisingclub.net/index.php/features/editori...
Of course this definition is not exactly correct or exhaustive anymore, this is just the origin. Now it’s understood as defined by the other commentators.
As a terminology aside online retail sales still uses “hard lines” and “soft lines” as product & organization categories!
I would include that as above the line. My understanding is ATL is for mass viewing. While BTL directly or reasonably targeted to the individual. I say 'reasonably' as often EDM/DM (emails and mailers) have broad targeting cohorts & elements but are considered BTL.
What is "the line"?