Maybe it's already a rule, and maybe it's not.
But... it seems that every time someone puts up a short but truly breaking diary, there's always a few FAQcists who chime in with "this is not a diary." So at the very least, I suppose there's some confusion about what the rule is.
So yes, I do support the concept of "real" diaries, and the eminently sensible rule that quick drive-by hits belong in open threads, not diaries. But... I'd also propose the following exception:
If something is really, truly breaking, then it's better to get it up quickly, even if it's really, really short. Get up the key stuff, the breaking news, right away, and then expand it when it's live, with commentary, context, whatever.
For example, there's a diary posted now about the retirement of Byron Dorgan. Yes, it's short. But that's truly breaking news. It's news that speaks for itself, without a crapload of commentary. I'd much rather get stuff like this right away, rather than wait 15 or 20 minutes for expanded commentary.
Agree or disagree if you want, but... that thar is my opinion. If the news is breaking -- truly breaking -- I want it ASAP. Even if it's (gasp) "not a diary."
Discuss.