Surprisingly, this request is not prompted by any specific problem I encountered. It's more from my uneasiness with updating my own nodes seconds after I post them (yes, I do preview first. Fingers still much faster than brain.)

Suggestion: in the database, label every reply with an id/timestamp/version/whatever of its parent. When rendering out nodes, mark them as "this reply was to an earlier version of a post" if that id does not match the current id of the parent node.

The problem it addresses is when an author updates a node with replies such that the replies are invalid or don't make sense. This way, at least readers would be warned that they should think before assuming that the replier is an idiot, and perhaps wonder instead about the original poster.

I suppose you could also allow repliers to update their posts to "certify" them with the latest version of the parent node, thereby removing the warning label. Not that they need bother.

I have no idea what the performance implications of this might be, although it seems like the parent node is already getting retrieved at the very least to print out its title. I'm also not sure if the problem it is addressing is big enough to bother with. But it popped into my head, so I thought I'd mention it.

Update: I could have just changed the entire contents of node to "anybody who replies to this node is a poopy head."

But I didn't.