The idea illustrated in this paper is very straightforward and practical in real world applications. The author designed a system that can capture design history and help improve the efficiency of such design process. In short, it is a snapshot system that help users quickly locate their past design sessions. Specifically, users collaborate using post-it notes on a white board equipped with cameras and projections. The design process is different post-it status over time.To help user quickly find the history snapshot, thumbnails and synopsis (bookmarks determined by team at a certain point) was implemented and shown on different timelines: main timeline, local timeline and branched timeline. As for user study, several scenarios was illustrated: reaching a dead end that needs to revert to a certain point, writing a summary for the session, find the rationale behind a decision and following up on a session. Although lack of qualitative analysis, the study shows that finding history timestamps is quick and smooth. The author did discuss several problems encountered during the study, including branches cause confusion, lack of visual comparison and merging etc.
In general, I really like this paper because it is very helpful in real world applications. Although this paper date back to 2002, but its methodology still remains very useful, not only for post-it style work, but for online teamwork in general. Specifically, similar problems we can encounter when team working on Google Doc. Although it is not face-to-face collaboration, other user’s current focus can be indicated by highlighted framed cursors in different colors that correspond to different user’s profile pictures. When looking for history changes, the part modified part is highlighted under different colors, and clearly express as add/delete/modify. However, some of the problems stated in this paper still remains a problem in real world scenarios, in a different way. Let’s discuss this for google doc for example, looking for revision history can still cause confusions, since listing all fine-grain modifications will occupy a lot of space, however for a better representation of the entire timeline, the snapshots cannot be too fine-grained, this threshold between fine or coarse-grain is hard to determine. One possible solution is a secondary timeline. When selecting a part / paragraph, the system can specifically show the snapshots of this specific selection over time, and a slider to adjust finer or coarser grain for such snapshots. Another common failure in this system is user failure to pay attention in online scenarios, it is hard to track what other users are doing unless they actively chat in the document-wide chatroom, or you will have to locate the specific user’s cursor and spend some time to see what he is doing. When the cursor stopped moving, you don’t doubt if the user stopped working, rather you suspect there is a network lag or something wrong with the system. To address this problem, we can reference MOBA game designs, in which to direct user’s attention, different cues were used: flashing lights, warning sounds, red exclamation mark to indicate danger, or yellow question mark to indicate missing. Although directly migrate this would be over-do for online document collaboration, it can well be designed in a way so that with proper sound and visual cues can direct users’ attentions.