Yeah I dunno, we’ve never had reports of lost posts – plus we save server-side drafts of posts as you type characters in the editor. Any unsubmitted post content is saved to the server about once every 60 seconds. You can test this yourself – start typing a reasonable amount of stuff in a new reply, then hard kill your browser (or turn your machine off, etc). Come back to the topic and your post will still be there in the editor, waiting for you to do something with it.
(sorry about the link bug – click your name/avatar in the left gutter, then click “show posts…” to see just your posts here.)
