PUBLIC MARKS with tags wikipédia & free

Markdown is a lightweight markup language, originally created by John Gruber and Aaron Swartz, which aims for maximum readability and "publishability" of both its input and output forms, taking many cues from existing conventions for marking up plain text in email.

Textile is a lightweight markup language originally developed by Dean Allen and billed as a "humane Web text generator". Textile converts its marked-up text input to valid, well-formed XHTML and also inserts character entity references for apostrophes, opening and closing single and double quotation marks, ellipses and em dashes.