As mentioned in a previous post, Varytale is a platform for interactive stories. It’s put together by Ian Millington, the same person who created the Undum tool, but Varytale goes quite a bit further.
By contrast Varytale comes with a complete authoring tool; a website where books are showcased and attractively presented online; the capacity (eventually) to use one of several payment schemes to charge for content; and feedback and statistics tools that allow the author to collect ratings and comments on content, and to see which story choices are especially popular or unpopular. These tools require vastly less coding than traditional interactive fiction, but they do allow for world state and player stats-tracking. (Some time back, I described why CYOA without world state is a bit too restrictive for most of what I want to write.)