Project Lazarus is your friend. 

https://addons.mozilla.org/en-us/firefox/addon/lazarus-form-recovery/
^ for anyone who hasn't heard of it (there is a chrome version as well)

When you're typing in a web form (the reply box counts as a form), it auto saves your text every few seconds so if something crashes, the site goes down, etc. you can just right click and recover what you were typing.