This is not, however, the first attempt to gin-up such software. We have long admired the work done some years ago at the Pacific Northwest National Laboratory in the ThemeRiver™ visualization.
It "...helps users identify time-related
patterns, trends, and relationships across a large collection of
documents. The themes in the collection are represented by a 'river'
that flows left to right through time. The river widens or narrows to
depict changes in the collective 
strength of selected themes in the
underlying documents. Individual themes are represented as colored 'currents' flowing within the river. The theme currents narrow or widen
to indicate changes in individual theme strength at any point in time. Status: An interactive proof of concept prototype has been developed. Download a QuickTime video about ThemeRiver (20MB)
strength of selected themes in the
underlying documents. Individual themes are represented as colored 'currents' flowing within the river. The theme currents narrow or widen
to indicate changes in individual theme strength at any point in time. Status: An interactive proof of concept prototype has been developed. Download a QuickTime video about ThemeRiver (20MB)We hope the PNNL will continue by giving us more of this intriguing tool.
