Firefox extensions are growing like mushrooms... 
Scribe is a Firefox extension that permits you to save your posts on web forms locally while surfing (XHTML format), so you could reload it next time.
 | It adds Word Processor like functionality to web forms, including opening and saving form entries as files. If you are a blogger, it could be useful during your blogging activities (for example if you've not a dedicated tool for blogging or during your feedback activity). |