What are discussion groups / email lists?
These are email affinity groups that allow people with similiar interests to
correspond via email through a central email server. Simply put...to talk to
the group you send an email to the list email address, the list email server
then takes care of distributing your email to all of the members. And you,
in turn, receive email from all of the other members from the list email
Some of the lists are very active and can generate hundreds of messages a week. Others, particularly the specialized ones, geneate only a handfull of messages in a given period. Some are 'chatty' like a social club, others are more straight forward and factual.
Only you can decide which type fits you best. And the only way that you can find out is to join. Have fun!