Markdown is a simple, human-readable markup language designed for general use. As of 2021, it's probably by far the most popular markup language for prose.

: ''Markdown is intended to be as easy-to-read and easy-to-write as is feasible.''

: ''Readability, however, is emphasized above all else. A Markdown-formatted document should be publishable as-is, as plain text, without looking like it’s been marked up with tags or formatting instructions. While Markdown’s syntax has been influenced by several existing text-to-HTML filters — including SeText, atx, Textile, ReStructuredText, Grutatext, and EtText — the single biggest source of inspiration for Markdown’s syntax is the format of plain text email.''

: ''To this end, Markdown’s syntax is comprised entirely of punctuation characters, which punctuation characters have been carefully chosen so as to look like what they mean. E.g., asterisks around a word actually look like emphasis. Markdown lists look like, well, lists. Even blockquotes look like quoted passages of text, assuming you’ve ever used email.''

http://daringfireball.net/projects/markdown/syntax

Some new wiki projects, such as Encycla (https://encycla.com), use markdown as their internal markup language instead of classical wikitext.