CYOA [samizdat.cc], short for Choose your Own Adventure, is a beautiful and sophisticated website devoted on revealing the twists and turns one takes when reading interactive fiction. A typical CYOA book is a collection of numbered pages of a few different types. Most pages tell a portion of the story, then finish by allowing the reader to jump to another page. A smaller number of pages tell a conclusion to the story and represent an endpoint with no further jumps.
Christian Swinehart subdivided these 'narrative' and 'endings' groups based on the number of choices offered (e.g. a 'branching' page or a 'choiceless' story page) or the goodness of the ending (e.g. from 'great' to 'catastrophic'), and then color-coded the pages accordingly. The resulting frequency dot plots, spanning about 12 different CYOA books published between 1979 and 1986, show a gradual decline in the number of endings and a decline in the number of choices available in the books. Other visualizations include distribution graphs (all pages lined up in a single row by group), branching decision frequency graphs (pages close together in the story flow are close together in the map, more frequent paths are brighter), and animated story paths (growing arcs depicting the possible page jumps within a book).
Next to the detailed descriptions, the website allows you to read a book ("Zork: the Cavern of Doom" by Steve Meretzky) for yourself (and enjoy the visualization to build up dynamically!), or to check out the beautiful animations (select and click 'play').