Yesterday, on the Rails list, messages were taking on average 26 seconds to get from sender's ISP to my ISP. Out of half a dozen making up a thread, the fastest was 20 seconds and the slowest was 35 seconds.
Today, on firstname.lastname@example.org, the average of a sample of twelve messages is 22.25 minutes. The fastest was 11 minutes 42 seconds, the slowest was 57 minutes.
If I ask a question and someone answers "immediately", I shall see the reply about 45 minutes after asking the question. That's like having a radio conversation with someone on Mars, when Mars is at its furthest from the Earth.
I guess anyone who wants the old level of responsiveness will have to use the Web interface - but then I see that signing up for a Google Groups account involves agreeing to only use it for personal, non-commercial purposes. In my case, that wouldn't be entirely true.
(Does anyone know what the terms and conditions are for email users, signed up by someone else?)