I'm drafting this blog in Sta.sh Writer, which should itself be a recommendation.
What is Sta.sh Writer? Here's $spyed's super fancy announcement:
Introducing Sta.sh and Sta.sh Writer! Tweet
What is Sta.sh?
What is Sta.sh?
Sta.sh is deviantART's new upload and submitting platform, home to all of your images, writings, Flash/animations, and everything in-between. It provides you with an area to place, organize, and perfect your artistic workings to submit to deviantART and beyond. A suite of features all in one, Sta.sh is here to make your online life a whole lot easier.
Drag & Drop, & Store
Drag and drop multiple files at one time quickly and easily. Submit immediately to deviantART, or take time to customize or enha
The fastest way to access Sta.sh Writer is by typing it directly into your browser:
sta.sh/writer--as long as you're logged in, it'll take you straight there. If you're not as much of a keyboardist, you can go to the Submit dropdown > Sta.sh > click on the Sta.sh Writer button in the upper right hand side.
No software necessaryAt this point, there's no way you haven't heard about the 'cloud'. (Stop looking at the sky.) My favorite thing about Sta.sh Writer is that it's cloud-based, which means that I can start writing in the middle of the night on my netbook or phone and pick up from where I left off, as long as I have an Internet connection. (It also autosaves, which is nice, although you should never rely completely on it; Word can lose data too.)
Since everything is in your browser, you don't have to worry about cross-compatibility between computers. You don't even have to download anything extra.
Also, you're not going to lose your text if something happens to your computer.
FormattingThe most obvious thing I have to say here is that you can slap a journal skin on. (Subscription necessary.) If you're into that stuff, there's lots to explore; I find it nice to be able to limit width when I actually submit work to dA, although I'm fine with the default look when actually typing.
Shortcuts like Ctrl+B for bold, Ctrl+I for italics work fine. (Ctrl+E/L/R don't, however.) If you only need basic formatting, you shouldn't have an issue, regardless of whether or not you know code.
LengthAside from content for dA (journals, shorter lit) I mostly use Sta.sh Writer for starting longer pieces. There is a character limit. FAQ #627: Is there a character limit for Poetry/Prose submissions? discusses the one for all text submissions; I don't know if it's set for Sta.sh, but I've run into it on one occasion and can confidently say you wouldn't be able to use Stash to write a novel unless you wanted to post everything as separate chapters.
(It was, however, fantastic for NaPoWriMo.)
LimitationsWhile Sta.sh Writer is the most convenient in-browser writing tool, it's important to note certain limitations. The program is fairly new and if you notice a bug, you should report it to the Help Desk. (To suggest enhancements, use the Suggestions Forum.)
You have to be mad to want Microsoft Word's grammar checking tool so let's never speak of that again, but as far as spellchecking goes, Sta.sh Writer only uses your browser's built-in spellchecker. Which means that if you have it turned off, you're not going to see squiggly red lines everywhere. (Okay, you could be a good speller too. That's a thing.) Blogging platforms behave similarly, so this shouldn't be new.
Anyway, if you're using this to write pieces you're planning to redraft in a different processor, it's important to note that there is currently no way to download a *.txt or *.doc version of your work. Everything is copypaste. Sta.sh is good about bringing in basic formatting (bold, italics, links, etc.) from other places, and LibreOffice seems to work just as well when copying out of Sta.sh, but there's no guarantee all of your formatting will be saved in whatever other writing program(s) you're using.
I know people have issues with the spacing when Word documents are pasted in, so I would stick to copying new text in from plain text editors like Notepad. Although, really, I use Sta.sh Writer for new stuff anyway, so I don't run into this.
Finally, if you're planning to dump in a lot of HTML/fancier formatting, expect things to go wonky at some point. I find that the Rich Editing mode is great as long as you're not manually entering code; once you switch to HTML mode, I recommend sticking with it, even though you will lose some of the fancy features.