The historical roots of IT-based monitoring in health care are described. Since the 1970ies monitoring has been spreading to more and more domains of health care and public health. Today one can observe monitoring of persons in many environments and regarding widely different questions. While these monitoring applications have been introduced ethical questions have been raised to balance the possible positive and negative outcomes of the approaches. Today IT-technology is entering many parts of our life – IT eventually became what had been coined already in the last century by IBM as “electronic dust” which one can find in every part of our environment. As most of these “dust-particles” are able to observe something one can also understand this development as a development into ubiquitous monitoring of nearly everything at any time. The foreseen ambient intelligence worlds are also spaces of ambient monitoring. This article describes this historical development. It emphasizes why ethical and data protection questions are an absolute must in most IT activities today.