Internet use for corporate sustainability reporting represents a complementary approach to consolidated, printed sustainability reports which have increasingly been published, in particular, by large companies in recent years. It enables companies to overcome the restrictions of printed sustainability reports regarding the extent of the information, its accessibility and comprehensibility as well as the interactivity and the engagement of stakeholders in a continuous dialogue. The paper explores the question whether and to what extent German companies have been using the internet for sustainability reporting since 2004. Based on three studies of the German DAX30 the paper analyses trends over a four year period and identifies areas where there is potential for further improvement.