To put a little more context to Glenn's post:

There are at least significant processes involved in the processing of
the RFC822 REPLY-TO: field

1) the poster's mail client

2) LISTSERV's use of the list definition keyword * REPLY-TO=

3) the subscriber's particular mail client with multiple REPLY options

The various combinations makes for some unhappy campers when they don't
reply to where they thought they were.

/Pete