[Mailman-Users] Date for Posts - How is it decided?

[Drew Tenenholz]

Folks --

What is the 'official' date for a post?  I am the admin for a small, 
moderated where the following seems to be happening:

1) The daily digest lists several posts from yesterday/early toady 
and has a delivery date of 'today'.
2) The message archive can be used to show the exact day the message 
was posted (today or yesterday).
3) Individual posts are being received with delivery dates exactly 
ONE MONTH in the FUTURE!

Is this a Mailman setting, or is could it be the moderator has set 
their clock incorrectly set?

Thanks in Advance,
Drew Tenenholz