I'm just brainstorming here, so please bear with me. I've just finished a video game named Mass Effect 2 (ME2). Like every other RPG, ME2 has a main plot that you play through. In addition, it's also got hours upon hours of extra content. You can explore planets that have nothing to do with the main story, but by doing so, you get to learn more about ME2's history, culture, etc. Time is a powerful device for making the audience care about the universe you've created. By providing all of those optional materials, ME2's developers definitely made me care. This made me wonder, could the same by achieved with novels? If only there was a way to provide some sort of optional content. But how? We could have a scene where two characters are just having a general chitchat. That won't work, though. We'll think it's not advancing the plot, and that the scene can be removed. Why can extra scenes be included in games, but not books? Well, we could have appendixes like in The Lord of the Rings. Many writers outline their stories, and when they outline, there are many things that don't make it into the final product. If only there was a way to share that content with readers, that would be neat. Please feel free to share your thoughts. Cheers.