On the open source front you get zettlr.com, a pure markdown WYSIWYM editor with image preview, pandoc integration for exporting groups of pages into whole docu

On the open source front you get zettlr.com, a pure markdown WYSIWYM editor with image preview, pandoc integration for exporting groups of pages into whole documents, support for Zettlekasten workflows, and academic references management. It's a one-man effort by a guy who created it for working on his PhD, but it's quite robust and usable despite a few small flaws (who should be corrected in version 2.0, likely coming during the year).