If you use markdown like I do on a Mac, you may notice that Quick Look does not render .markdown
files as documents, instead providing an icon only. If you have tools like iAWriter installed (I used to), they install a Quick Look plugin, and the markdown is rendered readable.
For the rest of us, Brett Terpstra of Marked and nvAlt fame has released an update to Fletcher Penney’s Quick Look generator.
Check it out at Multimarkdown Quick Look With Style. I’m using it.