diff --git a/conversations/migrations/0002_message_system.py b/conversations/migrations/0002_message_system.py
new file mode 100644
index 0000000..b09f2d4
--- /dev/null
+++ b/conversations/migrations/0002_message_system.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.7 on 2016-07-07 16:49
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('conversations', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='message',
+            name='system',
+            field=models.BooleanField(default=False),
+        ),
+    ]
diff --git a/conversations/models.py b/conversations/models.py
index 3322d19..40741d1 100644
--- a/conversations/models.py
+++ b/conversations/models.py
@@ -21,6 +21,7 @@ class Message(PonyConfModel):
 
     author = models.ForeignKey(User)
     content = models.TextField()
+    system = models.BooleanField(default=False)
 
     class Meta:
         ordering = ['created']
@@ -103,6 +104,8 @@ class ConversationAboutTalk(Conversation):
     def new_message(self, message):
         site = self.get_site()
         first = self.messages.first()
+        if not message.system and message.author not in self.subscribers.all():
+            self.subscribers.add(message.author)
         recipients = self.subscribers.all()
         data = {
             'uri': site.domain + reverse('show-talk', args=[self.talk.slug]),
@@ -117,8 +120,6 @@ class ConversationAboutTalk(Conversation):
                 'proposer_uri': site.domain + reverse('show-speaker', args=[message.author.username])
             })
         else:
-            if message.author not in self.subscribers.all():
-                self.subscribers.add(message.author)
             subject = 'Re: [%s] Talk: %s' % (site.name, self.talk.title)
             template = 'message'
             ref = first.token
diff --git a/conversations/signals.py b/conversations/signals.py
index 47b2bd1..a5bcfb0 100644
--- a/conversations/signals.py
+++ b/conversations/signals.py
@@ -38,7 +38,7 @@ def check_talk(talk):
 def notify_talk_added(sender, instance, author, **kwargs):
     check_talk(instance)
     message = Message(conversation=instance.conversation, author=author,
-                      content='The talk has been proposed.')
+                      content='The talk has been proposed.', system=True)
     message.save()
 
 
@@ -46,7 +46,7 @@ def notify_talk_added(sender, instance, author, **kwargs):
 def notify_talk_edited(sender, instance, author, **kwargs):
     check_talk(instance)
     message = Message(conversation=instance.conversation, author=author,
-                      content='The talk has been modified.')
+                      content='The talk has been modified.', system=True)
     message.save()