Would be cool to get a thread going on why people have backed projects in the past. Here is what Kickstarter has to say
Many backers are rallying around their friends' projects. Some are supporting a new effort from someone they've long admired. Some are just inspired by a new idea, while others are motivated to pledge by a project's rewards — a copy of what's being produced, a limited edition, or a custom experience related to the project.
Backing a project is more than just pledging funds to a creator. It's pledging your support to a creative idea that you want to see exist in the world.