Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
ContentTools - A small & beautiful WYSIWYG editor for HTML content.
Textile - Textile is a lightweight markup language originally developed by Dean Allen and billed as a...
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.
GitHub Flavored Markdown - GitHub uses "GitHub Flavored Markdown," or GFM, across the site--in issues, comments, and...
CKEditor - Real-time collaborative future-ready rich text editor