Why don't I get copies of my own posting to my Gmail account?
When posting a message to a list from a "gmail.com" address, a copy of the message won't appear in the your Gmail "Inbox". The MailmanLists server correctly delivers the message to your list and a copy of your post to the Gmail servers, but Gmail discards this copy.
To work around this, in your member settings, click on ".Yes" to receive an acknowledgement email when posting to the list. The acknowledgement email doesn't send you a copy of your posted messge, but it lets you know that it was received by the list.