Practically everyone has heard of Little Red Riding Hood, a fairytale of an encounter between a young girl and the Big Bad Wolf. One of the most popular versions of this tale was written by the Brothers Grimm. But what has a simple folk tale got to do with text stream visualization? And what is stream visualization? Stacked area charts, or stream visualizations, are very useful to show how topics in a single document or set of documents change and develop over time.