The problem wasn't instant propagation. It's loading in a timely
manner. Something delayed the original message's appearance in
Google's own database for a considerable time, making it look like
nothing had posted, and a check of the group confirmed that. But when
I reposted, both appeared.

The thing that will probably cause me the most reason to stop using
Google Groups, though, is that it has a posting limit. And doesn't say
what the limit is.

As for context, I recommend a threaded newsreader. I wouldn't post
anywhere without one.

--Blair