Markdown, a lightweight markup language, originally created by John Gruber and Aaron Swartz.
Markdown is a text-to-HTML conversion tool for web writers. Markdown
allows you to write using an easy-to-read, easy-to-write plain text
format, then convert it to structurally valid XHTML (or HTML). See the Syntax page for details pertaining to Markdown’s formatting syntax. You can try it out, right now, using the online Dingus.