Scrivener is a powerful content-generation tool for writers that allows you to concentrate on composing and structuring long and difficult documents. While it gives you complete control of the formatting, its focus is on helping you get to the end of that awkward first draft.
Wordie lets you make lists of words -- practical lists, words you love, words you hate, whatever. See who else has listed the same words, add citations and comments, and discuss
This HTML text editor brings to the web many of the powerful functionalities of desktop editors like MS Word. It's lightweight and doesn't require any kind of installation on the client computer.