A Discussion Mailing List is a two way communication tool. They are usually on a certain topic. Each subscriber can post messages that will be sent to everyone on the list. Others can reply back personally or to the entire list. When posting for the whole group, the message is sent via e-mail to an address that then forwards the message to the whole group.
Discussion Mailing Lists would also be a good resource for students that want to have current information on a topic. Again, they could search and find a list that meets their needs. Once they find a list they can post information and receive information via e-mail. This could be better than a broadcast list because they might receive information from many people rather than just one.
Another name for this type of list is listserv. Listservs could also be used to let students help each other. If all students had access to e-mail they could use the list to ask each other questions when they have difficulty with a subject.