Wordpress, man. Word. Press.
Wordpress just ate a 500-word post. Didn't save a thing. This happens everywhere.
Blogger's always doing something weird. Sorry it screwed you this time.
Happened to me once. Just finished a 600 word blog post on blogger. Bolded some text, then pressed CTRL+Z to undo AND ALL THE TEXT DISAPPEARED!
Lately, I can tell when blogger is going to eat my post. It won't preview properly. I've learned to highlight and copy everything and then close the post. It then tells me I'm logged in somewhere else. I have a Tablet that always logs me into google. Relogin, reopen the post and ctrl-V and I'm back to where I was.