If you're a fan of interactive fiction, consider www.myweft.com.

It's a free authoring tool and publishing platform for stories that branch.

Although it's currently bare-bones, it does include:

• A visual, map-based editor to help manage authoring complexity
• User accounts to save works-in-progress
• One-click publishing
• Export, so you can take your story with you
• A 60-second demo story that illustrates the principle of restricted choice

I'm actively working on it, so feedback is gold to me. Thank you.