Litewrite offers distraction free editing.
Ranked in these QuestionsQuestion Ranking
Pro Remote storage
Supports the remoteStorage protocol for privacy-aware personal data storage.
Pro Free and Open Source Software
Pro Distraction free
Pro Completely browser based
Pro Very minimalistic
Its without any frills and quite unadorned and yet rather functional. For those who like it plain and simple and open source and non-corporate this is rather good.