Casual Infovis is the use of computer mediated tools to depict personally meaningful information in visual ways that support everyday users in both everyday work and non-work situations.
It is a great read that focuses on the visualization needs and usage patterns of non-experts. They keenly identify characteristics of infovis that are meaningful to this group (including the personalization of infovis systems that I was trying to gesture at in my thoughts about the smartvote.ch system), and suggest ways to emphasize a type of information interaction that "exists outside focused episodes of work." I was particularly interested in their discussion of "utilitarianism" versus "usefulness," as well as their re-consideration of evaluation methods for "casual" infovis systems. Being entrenched in the world of media studies, I am in complete agreement with an ethnographic approach to visualization evaluation.
My only criticism of their argument is that they seem to distance the various types of (valuable) insight gained through the use of casual systems from the analytic insights ostensibly achieved with "traditional" infovis systems. Ideally, casual use and analytic insight need not be mutually exclusive processes. While a casual system should necessarily avoid the levels of complexity characteristic of deeply analytical ("work focused") visualization tools, they should still (I would hope) encourage an appreciation for analysis in non-expert users while emphasizing the types of approachability described in this paper.
Anyways, I am really looking forward to hearing them present this paper at InfoVis 2007, as well as the whole "Visualization for the Masses" panel. It's very exciting to see visualization being thought about in this way.