When I'm in the early stages of any project, whether that's a writing project or a software project, I tend to throw a bunch of ideas down on a big piece of paper, spacing out as-yet unrelated ideas, clustering related notes, and drawing connections between them, trying to work out how everything fits together.

In short, then, Scapple is a tool for getting early ideas down as quickly as possible and making connections between them. The main advantage of doing this in Scapple instead of on paper is that you don't run out of paper (the Scapple canvas expands to fit as many notes as you want to create), you can move notes around to make room for new ideas and connections, it's easy to delete and edit notes, and it's easy to export your notes into other applications when you know what you want to do with them.