IBM's History Flow tool is a visualization tool for a time-sequence of snapshots of a document in various stages of its creation. The tool supports tracking contributions to the article by different users, and can identify which parts of a document have remained unchanged over the course of many full-document revisions. The tool was developed by Fernanda Viégas of the MIT Media Lab and Martin Wattenberg and Kushal Dave of IBM.
Without explicitly referencing it, the history flow's visualization mechanism is mainly based on the transclusion beams mechanism that was introduced by Ted Nelson to show Transclusion.[1]
IBM Research has done an analysis of Wikipedia usage and edits using a history flow tool.[2]