How is Authorea different from ShareLaTeX and Overleaf?

Authorea Help

We get this question a lot, so here's an attempt to address some important differentiation points. 
1- Authorea is format agnostic. Overleaf and ShareLaTeX are built around LaTeX. For Authorea, LaTeX is just one of many potential formats. At the moment we offer LaTeX, Markdown, and HTML. We might implement more format in the future too. Being format agnostic is a huge advantage: Authorea is for everybody, and it requires no knowledge of LaTeX or any other markup language. Authorea's HTML editor is a true rich text WYSIWYG editor (What you see is what you get). It makes the experience of writing in Authorea identical to that in Google Docs or Microsoft Word. Users do not need to learn any complex markup. They use Authorea as they would use Google Docs with the additional scholarly features that make Authorea powerful: citation discovery and management, automatic bibliography, mathematical notation, tables, data, and one-click formatting.
2- Authorea is web native. ShareLaTeX and Overleaf bring the LaTeX desktop experience to the web. You compose LaTeX code in one window pane of the browser, press compile, and generate a PDF in a separate pane. While this writing paradigm is familiar to LaTeX writers (a small percentage of the scholarly community), it is entirely unknown and difficult to grasp for non-LaTeX users (the vast majority of scholars). Authorea has an intuitive interface, similar to most other web applications. Every document you write in Authorea becomes a beautiful webpage. Authorea is "web first".
3- Authorea produces professionally typeset and formatted papers in one click. For many LaTeX users, a major benefit of LaTeX is the fact that it produces beautiful, professionally typeset documents (PDFs). Overleaf and ShareLaTeX accomplish this in the most traditional way, you write LaTeX starting with a template and then compile a PDF that uses that template styling. Authorea separates format from content. All content created does not have a specific output format. At any point in time, you can export a version of your document (PDF, Word, etc) formatted in the style of your choice (e.g. Nature, Science, APA style, Biomed central, and hundreds of other styles). Why is this important? If you submit a paper to Nature and get rejected, you don’t have to spend a full day reformatting your paper and citations according to, say, Science style. Authorea does it for you in one click.
4- MS Word import and export. Since Authorea is not only for LaTeX users, we allow people to import and export their manuscripts in Word format.