This paper examines a number of the approaches, origins and ideals of context-aware systems design, looking particularly at the way that history influences what we do in our ongoing activity. As a number of sociologists and philosophers have pointed out, past social interaction, as well as past use of the heterogeneous mix of media, tools and artifacts that we use in our everyday activity, influence our ongoing interaction with the people and media at hand. We suggest that ones experience and history is thus part of ones current context, with patterns of use temporally and subjectively combining and interconnecting different media as well as different modes of use of those media. One such mode of use is transparent use, put forward by Weiser as ubicomps design ideal. One theoretical finding is that this design ideal is unachievable or incomplete because transparent and more focused analytical use are interdependent, affecting and feeding into each other through ones experience and history. Using these theoretical points, we discuss a number of context-aware system designs that make good use of history in supporting ongoing user activity.