This is another idea that we are are working on beside the fan-shaped visualization.  The basic rationale behind this visualization is to give the user a useful overview of the currently open tabs once she has opened to many of them to keep track of.  Ideally the user would want see different tabs differentiated by relevance or grouped in meanigful clusters.  While further brainstorming on this we concluded that one of the most useful criterias would be by chronological proximity.  Tabs that have been opened within a certain timeframe are quite likely to belong together. Based on these considerations, we came up with the following sketch.

The x-axis of the screen represents the time for which the browser has been open. The scrollbar can be used to only highlight a certain timeframe and to move that frame back and forward over time.  The time axis would also expand at those times where the most tabs are placed, so that there will be sufficient space to place them.  Finally, some shading in the background would indicate night and day time, to provide some additional chronological orientation.

The y-axis represents relevancy of the tabs.  Relevancy will not be strictly defined by a single metric, but rather be a combination of multiple metrics that might indicate such significance of the tab.  These would include:  time since the tab has been viewed, frequency of viewing that tab, time spent on the tab, popularity of the open website, and possibly more.  The assumption is that less relevant tabs (e.g. a search result that you just briefly looked at) would sink to the bottom of the tab, while the more relevant ones (the ones that you probably want to find) would stay at the top.

Additional visualization features include:

• a sticky area at the top left of the screen, with tabs that are constantly kept open and often revisited
• highlighting of tabs that haven’t been looked at yet
• grouping of tabs through colored borders. for tabs that have an opening relationship or that have the same domain (e.g. “*.umich.edu”)
• connectors between tabs that have an opening relationship

From the sketch above we went on to create a little more high-fi version of this visualization.  Not all the visualization features from above are included in this version yet, but it should give a relatively accurate idea of how this could look like on the computer later.

Trade-offs

We think this type of visualization provides a pretty good way to give a useful overview of the currently open tabs, but it also has a couple of downsides:

• it is a pretty heavy type of visualization that would require you to almost completely leave your current browsing context
• especially with many tabs and a long timeframe (which unfortunately is on of the main targeted contexts) it could become a little busy
• it doesn’t provide a very complete browsing history, since it only displays currently open tabs and websites

Concerning the last issue about a more complete browsing history that would show exactly which website you head open in which tab for how long and which website you were viewing at any time, we considered an additional view to our visualization.  As indicated in the bottom left corner, the user could switch between the depicted overview mode and another view that would give you a complete browsing history using time bars (see our previous idea) within the same frame.