If you have at login for the Yahoo group, you should be able to use ThunderBird to connect and download all the of list email, to keep it as an archive (it will be in MBOX format). I'm not sure how you would then push it back up into an online email list, however.
MIT Institute Archives and Special Collections
From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of Chris Edwards
Sent: Tuesday, June 02, 2015 1:20 PM
To: [log in to unmask]
Subject: [CODE4LIB] Migrating a Yahoo group's messages?
I belong to a listserv that, unfortunately when it was established back in 2007, was set up as a yahoo group. m looking for a way to archive the group's email and move it to another platform, something that will be searchable and will NOT be a yahoo group.
Has anyone here ever had to do something like this? This group was Neo-ized<http://yahoogroupedia.pbworks.com/w/page/68466246/Yahoo%20Groups%20Neo#History> along with the others back in 2013 and Im having trouble finding any tools to export the messages. There seems to be a solution<http://www.personalgroupware.com/> but this software dumps the messages into a proprietary data base that can't be read any other way. There is another perl script<http://archiveteam.org/index.php?title=Yahoo!_Groups> that looks good, but may not work with the newer style of yahoo group.
Any suggestions or assistance would be most appreciated.
Head, Digital Services
Getty Research Institute