Authorea is an online social authoring platform for the collaborative writing of research articles. Its versioning control system is entirely based on Git (every article is a Git repository). But Git functions in the backend, so that users who are not familiar with (or do not care about) Git can just use it as an editor and still have all changes logged as commits. In other words, Authorea allows power users (who know Git) to easily write papers in collaboration with regular users (who don't know Git). Authorea's frontend allows you to enter text in LaTeX or Markdown, as well as figures, and equations (in LaTeX or MathML). Authorea renders and compiles everything to the web (HTML5), in addition to PDF (export to numerous journal formats is provided).