diff --git a/cfp/signals.py b/cfp/signals.py
index 57cb73c..6d5ddfb 100644
--- a/cfp/signals.py
+++ b/cfp/signals.py
@@ -59,12 +59,18 @@ def send_message_notifications(sender, instance, **kwargs):
         else:
             user = thread.volunteer
         dests = [ (user, user.name, user.email) ]
+        if message.subject:
+            user_subject = None
+            staff_subject = None
+        else:
+            user_subject = _('[%(conference)s] Message from the staff') % {'conference': str(conf)}
+            staff_subject = _('[%(conference)s] Conversation with %(user)s') % {'conference': str(conf), 'user': str(user)}
         if author == user: # message from the user, notify the staff
-            message.send_notification(sender=sender, dests=staff_dests, reply_to=reply_to, message_id=message_id, reference=reference)
+            message.send_notification(sender=sender, dests=staff_dests, reply_to=reply_to, message_id=message_id, reference=reference, subject=staff_subject)
         else: # message to the user, notify the user, and the staff if the message is not a conference notification
-            message.send_notification(sender=sender, dests=dests, reply_to=reply_to, message_id=message_id, reference=reference)
+            message.send_notification(sender=sender, dests=dests, reply_to=reply_to, message_id=message_id, reference=reference, subject=user_subject)
             if author != conf:
-                message.send_notification(sender=sender, dests=staff_dests, reply_to=reply_to, message_id=message_id, reference=reference)
+                message.send_notification(sender=sender, dests=staff_dests, reply_to=reply_to, message_id=message_id, reference=reference, subject=staff_subject)
     elif hasattr(thread, 'talk'):
         message.send_notification(sender=sender, dests=staff_dests,
                                   reply_to=reply_to, message_id=message_id, reference=reference)
diff --git a/cfp/views.py b/cfp/views.py
index a984d62..44f34ce 100644
--- a/cfp/views.py
+++ b/cfp/views.py
@@ -213,11 +213,14 @@ def volunteer_details(request, volunteer_id):
     volunteer = get_object_or_404(Volunteer, site=request.conference.site, pk=volunteer_id)
     message_form = MessageForm(request.POST or None)
     if request.method == 'POST' and message_form.is_valid():
-        message = message_form.save(commit=False)
-        message.author = request.user
-        message.from_email = request.user.email
-        message.thread = volunteer.conversation
-        message.save()
+        in_reply_to = volunteer.conversation.message_set.last()
+        send_message(
+            thread=volunteer.conversation,
+            author=request.user,
+            subject='',
+            content=message_form.cleaned_data['content'],
+            in_reply_to=in_reply_to,
+        )
         messages.success(request, _('Message sent!'))
         return redirect(reverse('volunteer-details', args=[volunteer.pk]))
     return render(request, 'cfp/staff/volunteer_details.html', {
@@ -958,11 +961,14 @@ def participant_details(request, participant_id):
     participant = get_object_or_404(Participant, pk=participant_id, site=request.conference.site)
     message_form = MessageForm(request.POST or None)
     if request.method == 'POST' and message_form.is_valid():
-        message = message_form.save(commit=False)
-        message.author = request.user
-        message.from_email = request.user.email
-        message.thread = participant.conversation
-        message.save()
+        in_reply_to = participant.conversation.message_set.last()
+        send_message(
+            thread=participant.conversation,
+            author=request.user,
+            subject='',
+            content=message_form.cleaned_data['content'],
+            in_reply_to=in_reply_to,
+        )
         messages.success(request, _('Message sent!'))
         return redirect(reverse('participant-details', args=[participant.pk]))
     return render(request, 'cfp/staff/participant_details.html', {
diff --git a/mailing/models.py b/mailing/models.py
index 3d023a4..1a2067d 100644
--- a/mailing/models.py
+++ b/mailing/models.py
@@ -68,7 +68,7 @@ class Message(models.Model):
     class Meta:
         ordering = ['created']
 
-    def send_notification(self, sender, dests, reply_to=None, message_id=None, reference=None, footer=None):
+    def send_notification(self, sender, dests, reply_to=None, message_id=None, reference=None, footer=None, subject=None):
         messages = []
         for dest, dest_name, dest_email in dests:
             dest_type = ContentType.objects.get_for_model(dest)
@@ -92,7 +92,7 @@ class Message(models.Model):
             if footer is not None:
                 body += footer
             messages.append(EmailMessage(
-                subject=self.subject,
+                subject=subject or self.subject,
                 body=body,
                 from_email='%s <%s>' % sender,
                 to=['%s <%s>' % (dest_name, dest_email)],