Why join a Group?
To share an interest, discover more about something? There are hundreds of groups from writers to sport fans all blogging on the internet. There are groups within groups such as Face book, and than for example the David Bowie group page. There you have a public and private group. You could just join David Bowie website group instead of the facebook group. Interesting!
What can you add to a group?
What do you expect from a group?
What groups are worth pursuing? Is there communication within the group? Do they achieve anything?
How can you tell?
First know what you want from the group and than start by asking questions.