Inside a hub there is the Messages feature. Messages are broken up into two categories: announcement and discussion. Essentially, announcements are designed to be quick one-way messages from admins to members. Discussions are reserved for ongoing conversations between all the members in a hub.
1. Are designed to be one-way messages (only from admins to members by default; this can be changed)
2. Can be sent as a text message too!
3. Replies to announcement emails can only go back to the sender
1. Are designed to be conversational messages among the people of a hub
2. Can be initiated and take place all through email using the hub's e-mail address
3. Have formatting options when created inside MemberHub
4. Can be configured so that replies go back to the send or back to the entire hub