Why do we use Google Groups?
Firstly - like everything else about this site, it's cheap (as in free) and available to anyone as long as they have a Google account. It's also easy to transfer to a new owner/manager should that ever need to be done.
Secondly, it makes adding images etc. easy, with no separate hosting required.
Thirdly - it works via email (so you can read and reply to messages without having to use a web browser) as well as on the web and you can choose how often you receive the group's emails yourself.