I think that there should be an option allowing to archive mails according to date of reception of the posts by mailman, and not date set by user who sends it. That would prevent dates from the future in the archive: 2006, 2011, 2013, 2024, which you can see in many lists, like for example mailman-users archive: http://mail.python.org/pipermail/mailman-users/

Some archivizers determine messages' date by default according to Received field:

======= http://www.mhonarc.org/MHonArc/CHANGES

1998/02/18 (2.1.1)

o  Added DATEFIELDS resource.  The resource allows the user to
   specify the fields (and order) that are checked when
   MHonArc extracts the date of a message.

========

http://www.mhonarc.org/MHonArc/doc/resources/datefields.html

By default. mhonarc looks at the Received fields of a message to determine a message's date. This tends to be more accurate as it tells when the message was actually received (it is better to trust a date/time you have control over vs what the sender has control over). However, you may want to have the date based upon the time the sender composed the message. The Date field usually reflects the composition date.

I don't know if it is foolproof, but I would wish also pipermail to look rather at the received date, than sender composed date (which can be 2024 or something). It really looks strange when there are so many dates from future stored in archive... I'd prefer to have a few hours error (if any) in recognizing the date, than a few years one.

Regards Andy