Starting from now on, Blogger will periodically send a copy of the text, title, labels, etc. to their servers in case any accidents happens (e.g. browse or OS crashes) before you finish a post. Every once a minute, Blogger will autosave your post (unless you type a lot, in which case they'll save as soon as you stop typing). However, Blogger won't autosave posts that are currently published, since you don't want your readers to see your updates while you're working on them.
One thing that I find annoying, as pointed out by Ionut, the 'Publish' and 'Save' button have switched places.
|Related: Blogger Buzz|