What’s Happening: Work is underway to add native Markdown import support to LibreOffice Writer. This development, led in collaboration with a Google Summer of Code (GSoC) developer, aims to enable opening and editing of Markdown files (.md) using the MD4C Markdown parser.
In general: you don’t need any specific app to use Markdown files, you can just read them in a text editor. I’ve come to really like these kinds of raw-readable formats - usability without special tools can be incredibly useful depending on the situation.