At Gaggle Mail we see a wide variety of groups of all sizes discussing a wide variety of topics. Each group is comprised of a set of people who share a common interest and choose to use email to facilitate their discussion. They send messages, share pictures and make plans – just like on a social network.
The thing with Facebook is that it was designed to BE a social network. Over many years of use by billions of people it’s been honed to optimise for “socialness”. Every interaction has been optimised to achieve a certain goal; improve engagement, encourage ‘likes’, make friends, be more social.
You are socialising within their system, by their measures. All their tricks and nudges to optimise for their metrics change your behaviour. Maybe they change you for the better; making you more social, connecting with more people but it’s not you, it’s you + them.
By comparison email is just message passing – it’s a post office. It won’t encourage you to post a message or pester a friend who hasn’t replied to your message. It won’t go looking for people like you to connect with.
As a result of this, socialising over email is much more organic, nobody is going to hold your hand and show you how to socialise. With email your group has to survive by it’s own merits alone – email isn’t going to step in and help.