It started with WriteRoom, offering fullscreen, distraction free writing on the Mac. It became hugely popular because it let you focus on One Document at a Time:
Then there was iA Writer – first for the iPad, later also for the Mac. It too became hugely popular, partly because it lets you focus on One Sentence at a Time:
Now, Grandview. It is bound to become the next big thing, because it lets you focus on One Word at a Time:
To hell with context.