This paper examines the concept of weak signals: its basic idea presented by Igor Ansoff and its later developments. We argue that recent futures studies have essentially deepened the analysis of this concept, which originally lacked an accurate definition. Placing weak signals in the general context of futures research has provided the concept with a theoretical point of attachment and linked it with other futures concepts – such as strong signals and trends. Recent studies have also increased the applicability of the concept of weak signals, specifying ways in which signals can be identified, collected and interpreted. Consequently, a number of empirical examples of the analysis of weak signals are nowadays available. In the present paper, we summarize and evaluate both theoretical contributions and managerial implications of these new approaches. While emphasizing the advancements of research, we also want to point out that Ansoff not only was a pioneer in the field, but developed many ideas that are still applicable today. We conclude our paper by suggesting directions for the further development of weak signals research.