Abstract
We propose a conceptual model for explaining how Web ads work. The model specifies firstly, advertising input variables in terms of content and structure, with some of the structure variables being unique to Web advertising. Mediating these are ad-processing variables, and most importantly, the variable we call the Web ad schema. Moderators of the schema include Web navigation ability and, for the product advertised, category need and category expertise. Following ad processing, the final two stages of the model are the same as for general advertising, namely ad-based and brand-based communication effects and action. A series of hypotheses derived from the model are listed for future research. Also, measures of the main variables are indicated.