joke Emphasize IT - software development in Schönewalde/Germany by Martin Hartnagel

Why did the developer use Markdown for his website?

Because he wanted to keep things simple, and he heard it was headless (no pun intended!).

(Note: This joke plays on the double meaning of "headless" - both a literal term related to physical structure and a metaphor for a content management system without a specific design or front-end.)