Review App Settings -> Other
If you would like to allow members to send private messages to one another, enable this option. Private messages are sent via regular email but the sender will not see the receiver’s email unless the receiver chooses to reply.
You can also use this page to enable email notifications for members to receive whenever a listing receives a review or a photo or video gets a comment. Members need to opt into each notification and may stop “watching” an item at any time.