Internet advertising has gone from focusing mainly on click-through to focusing on brand effects. This means that websites and advertising networks need to demonstrate that brand effects are possible and can be measured. This paper discusses the measurement of brand effects in general and presents an approach to measuring the brand effects of Internet advertising. Results from 13 campaigns show that brand effects are possible, but, like advertising in other media, they cannot be taken for granted. The paper also shows how the effects of Internet advertising (to some extent) can be isolated from the effects of other advertising.