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
You can choose whether to send a message as an Announcement or Discussion on any New Message pop-up.