Through The Line (TTL)

Through the line refers to an advertising strategy involving both above and below the line communications in which one form of advertising points the target to another form of advertising thereby crossing the "line". An example would be a TV commercial that says 'come into the store to sample XYZ product'. In this example, the TV commercial is a form of "above the line" advertising and once in the store, the target customer is presented with "below the line" promotional material such as store banners, competition entry forms, etc.
(source: WiKiPedia)