History Flow is a tool created by IBM’s reseach team to study the history of collaborative documents. Specifically, they study how subjects on Wikipedia evolve over time. I found out about History Flow over at Nate Koechley’s blog. As the IBM folks say…

history flow provides answers at a glance to questions like, Has a community contributed to the text or has it been mostly written by a single author? How much has a particular contributor influenced the current version of the document? Is the text’s evolution marked by spurts of intense revision activity or does it reflect a smooth transition from its beginning to the present?

Here’s a screen shot of one of the History Flow displays for term Islam.

This and Jon Udell’s screencast looking at how the the heavy-metal umlaut page on Wikipedia evolved give a good overview on how the Wikipedia community is working.