To manage your list membership, go to http://listserv.kent.edu. Click on List Subscriber Login on the left-side menu. After you log in, you can choose the list you wish to manage (e.g., KSUSLIS-L is the SLIS listserv). This site will also allow you to view an archive of previous messages.
Next click on Subscribe or Unsubscribe on the right-side menu. This takes you to the page where you can add/remove yourself from the list, modify how you receive messages (e.g., digest vs. single messages, text vs. HTML, etc.), choose whether you get a confirmation of any posts and more.