SEAS has migrated mailman lists to Google Groups, which provides the same functionality of mailman lists. To manage Google Groups, you must have a g.harvard.edu email address. To have a Google Group created, please follow the instructions at http://g.harvard.edu/faqs#groups-2
Once you have a g.harvard.edu email address, you can manage your Google Group by:
browsing to groups.google.com
Click on the 'My Groups' image
click the link 'switch organizatinal view to harvard.edu'
You will then see any Google Groups you are either owner of or member of.
If you are a owner of a group, you can then manage group subscriptions
More information on administering Google Groups can be found at https://support.google.com/a/answer/167085?hl=en