Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
ContentTools - A small & beautiful WYSIWYG editor for HTML content.
Asciidoctor - In the spirit of free software, everyone is encouraged to help improve this project.
SquareSpace - Squarespace is the easiest way for anyone to create an exceptional website. Pages, galleries, blogs, e-commerce, domains, hosting, analytics, 24/7 support - all included.
pandoc - Pandoc is a Haskell library for converting from one markup format to another, and a command-line...
CKEditor - Real-time collaborative future-ready rich text editor