WikiChanges is a web-based tool for exploring Wikipedia article's revision history.
The revision activity of Wikipedia articles is strongly related to the attention captured by the topic(s) over time. As an example see the WikiChanges profile for the Tour de France article. You can find other examples in the popular plots page.
A Greasemonkey script is also available for embedding a revision activity sparkline next to the article's title (see image below).
WikiChanges Greasemonkey Script (click to install)
This software has been developed at the IRlab based at FEUP, Portugal.