I'm just guessing here, as I don't know for sure, but most mailing
lists (such as Google Groups, which this list uses) don't email you
when you post a message - but does send an email to everyone else in
the group. Replies to your message, since they are sent by other
people, you *do* receive.
Hope that helps... it might be explained somewhere in the Google
Group's help but can't find it.
Robert