I am not really fond of using text-areas in my web browser for authoring blog posts. Emacs has excellent text editing capabilities, and it has Org-Mode which is perfect for authoring structured text, like blog posts.
There is a lot of functionality in Org-Mode; it can be used for taking notes, managing TODO-lists, time planning, GTD (Get Things Done) and much more. And, as with all things Emacs, I've only touched on a small part of what it offers.