Some thoughts from the Amaxus people on keyboard-only ways to add formatting and html links in rich-text editors or text-areas using just the keyboard.
They consider these options: Automatic Markdown Conversion, and Inline Formatting (introduce a keyboard shortcut that initiates ‘inline formatting’ - basically shows what the shortcut keys are for different types of formatting and which gives you an easy way to set which text the formatting will apply to).
Also, some Hacker News comments on that post.
My interest in this is how we can have editors that can handle structure (the formatting and link information requires structured information. but also stuff like the structure of code and XML) in a fluid fashion. I think there's a lot of room for improvement there.