diff --git a/sugar/activity/activity.py b/sugar/activity/activity.py
index 99070d2a..85f660c6 100644
--- a/sugar/activity/activity.py
+++ b/sugar/activity/activity.py
@@ -510,6 +510,9 @@ class Activity(Window, gtk.Container):
         
         private -- bool: True to share by invitation only,
             False to advertise as shared to everyone.
+
+        Once the activity is shared, its privacy can be changed by setting
+        its 'private' property.
         """
         # FIXME: Make private=True to turn on the by-invitation-only scope
         if self._shared_activity and self._shared_activity.props.joined: