Markdown Sharp, initially called Markdown.NET, a C# implementation of the Markdown text processor, has been open sourced by Stack Overflow.
Markdown is a text-to-HTML conversion tool initially written in Perl by John Gruber who released it back in 2004 under a BSD license. Markdown is one of several lightweight markup languages - AsciiDoc, BBCode, Textile, etc.- and has got some traction over the years being employed by websites like Stack Overflow.
There are several Markdown implementation besides the original one done in Perl: PHP Markdown, Markdown.NET, Showdown/JavaScript, Discount/C, RDiscount/Ruby. Stack Overflow has been using WMD, a JavaScript implementation of Markdown, on the client side and Markdown.NET on the server side. WMD was open source from the beginning, and it was the effort of reverse engineering the original WDM/JavaScript written by John Fraser of AttackLabs. The server-side C# implementation has been recently open sourced as Markdown Sharp with some improvements, bug fixes and additions:
- included relevant links, documentation, and related files
- added MDTest 1.1 test suite
- added Simple test suite
- both NUnit and console runnable tests
- standard Benchmark with short, medium, and long Markdown samples
- refactored and profiled for 2x – 5x more performance
- the Stack Overflow specific changes (such as stricter italics/bold) are configurable, so you can toggle them on and off.
Markdown is useful to writers who want to use a simpler-than-HTML markup language that later can be converted to HTML. Also, websites can use it to let users enter comments in plain text which then are converted to HTML for publishing.