Purpose
This paper seeks to explicate the notion of “semantics”, especially as it is being used in the context of the internet in general and advertising in particular.

Design/methodology/approach
The conception of semantics as it evolved within linguistics is placed in its historical context. In the field of online advertising, it shows the limitations of keyword‐based approaches and those where a limited amount of context is taken into account (contextual advertising). A more sophisticated notion of semantic targeting is explained, in which the whole page is taken into account in arriving at a semantic categorization. This is achieved through a combination of lexicological analysis and a purpose‐built semantic taxonomy.

Findings
The combination of a lexical analysis (derived from a dictionary) and a taxonomy (derived from a general encyclopedia, and subsequently refined) resulted in the construction of a “sense engine”, which was then applied to online advertising, Examples of the application illustrate how relevance and sensitivity (brand protection) of ad placement can be improved. Several areas of potential further application are outlined.
Originality/value
This is the first systematic application of linguistics to provide a solution to the problem of inappropriate ad placement online.