Scapple comes from good stock: it is produced by the folk at Literature and Latte, who brought us Scrivener, a writer’s best friend (after inspiration and momentum). Scapple is a free–form note–taking app. It allows you to type anywhere on the page, and notes can be connected by arrows.
Hm, a mind–mapping app, you say. Not quite, since you can use Scapple without relying on any central idea, linkages or hierarchies. It is more of a brainstorming, content development app. I use Scapple to develop scenes for my novel. Let me show you what I mean.