Markdown is a powerful syntax and tool that enables us to more easily write content for the web.
Markdown is a readability-focused way to author content for the web. You can think of it as a language, although it's technically not. That's because browsers can't read markdown. Content on the web must ultimately be HTML. Therefore, markdown is really two things:
If you want to add a heading in HTML, you need an opening and closing tag, like this:
With markdown, you use a series of hashes at the beginning of the line to indicate 1) that it is a heading, and 2) which level of heading it should be.
The above HTML, written as markdown, looks like this:
# Heading 1
## Heading 2
### Heading 3
#### Heading 4
##### Heading 5
###### Heading 6
More than anything, markdown is a minimalistic means of specifying structure to your content. It's easy to read and write the content while still understanding its structure.
There are many more reasons to use markdown. Shoot, I'm using it right now in an application called Bear. But of all the reasons, this is why I write with markdown virtually every day:
Markdown was created by John Gruber in 2004. The "official" syntax can be found here, though there are variations on it which extend its behavior. One of the most popular is GitHub Flavored Markdown, which adds a few features like tables, task list items, and strikethrough text.
The original markdown parser was written in Perl. Today there are many parsing libraries available to you, depending on the language you're using.
They tend to be fairly easy to discover, too. Here's a nice article from CSS-Tricks if you're having trouble finding or choosing the right parser for your project.
There are tons of references out there, so I won't go through an exhaustive list. But I'll start you with The Markdown Guide, which is an excellent resource when getting started. In fact, their Getting Started page is a great place to jump to next.