It was inspired by Twine (http://twinery.org/) and I strongly reccommed checking out that project to see if it suits your needs first. It's a much more mature project and has been used to create a good number of stories already.
I wrote StoryTeller because of two issues I had with Twine (at least at the time I started this project). Most important was the fact that it did not have good support for random events*. I wanted to create something closer to a gamebook (think Lone Wolf) than a Choose-Your-Own-Adventure story. A much more minor issue was that Twine insisted on using a chapter's unique identifier as its displayed heading. This made it impossible to have two pages with the same title.
*Note: I've since been informed that Twine now has better support for random events (see here, or here).
Another project to check out is Undum (http://undum.com/).
Download StoryTeller v0.3 (This includes detailed documentation on how to use it.)
To discuss anything to do with StoryTeller, visit its Subreddit
If you are interested in the inner workings, StoryTeller's source code is hosted on GitHub.
Feel free to use StoryTeller and its source code in whatever way you like.