If you happen to still use Firefox, there's an extension It's All Text that allows you to use an external editor like vim for textarea input. https://addons.mozilla.org/en-US/firefox/addon/its-all-text/

There are somewhat similar extensions for Chrome to get the same effect, but requires a more elaborate setup to get around the sandboxing used by Chrome. http://superuser.com/questions/261689/its-all-text-for-chrom...