I think I misspoke, and meant the draft feature. It's not something I remember LiveJournal being able to do, but that was long enough ago that I wouldn't swear to it. I was dazzled when Dreamwidth implemented it. Previously I'd been relying on a Firefox add on called Lazarus, I think, to save the day in the event of unexpected or undetected logouts, and it was only so-so at that. But what got rolled out here worked perfectly.

Thanks for letting me know what it's actually called!