In the 1960s, Swedish address practices underwent a change from an intricate system of honorifics to universal use of the informal second-person singular du. This study challenges the common characterisation of this so called “du-reform” as very quick and straightforward. Previous studies, relying on reported usage and written language, suggest that the formal pronoun ni was considered impolite, while the informal du was restricted to use amongst family and close friends. The study uses advertising films to trace diachronic usage patterns in dialogue and in addressing the viewer. It shows evidence of change over a period of fifteen years. It also shows that the formal address pronoun ni and informal address by du were both used in addressing the viewer long before the du-reform. The du-reform is a noteworthy change in European politeness behaviour. Today, the informal du is the unmarked address form in Swedish.