Email Groups; A Brief Guide

Email Groups Or Lists are a simple way to share email correspondence among a number of users, known as Members. The group hosting company duplicates any email sent to the Group email address and sends a copy to everyone subscribed to the Groups members list.
When you reply to a Group email this to is duplicated to every member. this means that ALL members can read ALL the emails, known as "Posts" that are sent to the group and can join in with any "Thread" or topic.

Groups have an Owner, the person who created the group.
there may also be Managers, appointed by the group Owner, who assist with the running of the Group.
Groups can be Public, which means anyone can join the group members list (subscribe) or they may be Private which means only the Owner/Managers can subscribe new members.

Some Groups will have additional features such as a Group website or home page, the facility to upload group files or pages to the group website and an archive of group posts (emails).

Each Group will have it's own rules and guidelines.
There are Groups for almost any topic you could think of. to search for groups that may interest you try the two biggest group host companies, Yahoogroups & googlegroups.