Engrafting support staff into dialogues between users and customer support systems can compensate for system design flaws. Further, such dialogues can give grounds for system development. This article surveys the levels of interactivity of user support systems, where overt or covert support agents take an active part in the communication between a customer and a system. The main purpose is to demonstrate the prevailing lack of multimedia outputs in the tools supporting human intervention in systems with a graphical user interface (GUI). This is followed by an account of experimentation with human support engrafted in a web system that has a fuller range of GUI expression. The experiment explores the possibility of using multimedia in intervention in human-computer interaction and how such intervention can be built when it is not yet part of the augmented system.