Scrivener is a powerful content-generation tool for writers that allows you to concentrate on composing and structuring long and difficult documents. While it gives you complete control of the formatting, its focus is on helping you get to the end of that awkward first draft.
Substance is a fully web-based document authoring and publishing platform. With Substance, writers, journalists, scientists and everyone else who's interested in publishing can use an open platform for writing and sharing articles.