Grammarly - Clear, effective, mistake-free writing everywhere you type.
Daily Prompt - Become a better writer
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Day One - A simple journal application for the Mac, iPhone, and iPad. AboutTo learn more about Day One, see these two excellent reviews . PublishPublish is not available in Day One 2.
Editsaurus - Highlights potential pitfalls in your writing to encourage good habits.
My Old Business - Marketplace for entrepreneurs to buy and sell established websites or online business.