The default ListServ subscription option is to receive each message as it arrives.  If you are subscribed to a very busy list, you may want to change your option to Digest so that you only receive one message a day that contains all of the day's postings.

1. Login to Listserv with your Listserv email address and password.
2. Click on the list you wish to change
3. Click the menu button (3 horizontal lines) and choose Subscribe/Unsubscribe
4. Change the Subscription type to Digest HTML
5. Click Update Settings to save your changes.

Lsoft has a video tutorial with instructions