There are a whole slew of these things sprinkled throughout Network land. Whenever anyone sends mail to the list, it is sent to all the subscribers. Like todays specialty 'lifestyle' magazines, every list discusses a different, narrow topic.
Every list has a home.
One node might support several lists. For example, There is a list called skivt-l , a list that discusses skiing in Vermont. This list lives at node list.uvm.edu. Pat does not use Pat's address. Pat does not use Pat's address.