diff --git a/sugar/activity/activity.py b/sugar/activity/activity.py
index 553b1a1a..f63174a7 100644
--- a/sugar/activity/activity.py
+++ b/sugar/activity/activity.py
@@ -448,13 +448,22 @@ class Activity(Window, gtk.Container):
         self._shared_activity = activity
         self.emit('shared')
 
-    def share(self):
-        """Request that the activity be shared on the network."""
+    def share(self, private=False):
+        """Request that the activity be shared on the network.
+        
+        private -- bool: True to share by invitation only,
+            False to advertise as shared to everyone.
+        """
+        # FIXME: Make private=True to turn on the by-invitation-only scope
         if self._shared_activity and self._shared_activity.props.joined:
-            raise RuntimeError("Activity %s already shared." % self._activity_id)
-        logging.debug('Requesting share of activity %s.' % self._activity_id)
-        self._share_id = self._pservice.connect("activity-shared", self._internal_share_cb)
-        self._pservice.share_activity(self)
+            raise RuntimeError("Activity %s already shared." %
+                               self._activity_id)
+        verb = private and 'private' or 'public'
+        logging.debug('Requesting %s share of activity %s.' %
+                      (verb, self._activity_id))
+        self._share_id = self._pservice.connect("activity-shared", 
+                                                self._internal_share_cb)
+        self._pservice.share_activity(self, private)
 
     def _realize_cb(self, window):
         wm.set_bundle_id(window.window, self.get_service_name())
diff --git a/sugar/presence/presenceservice.py b/sugar/presence/presenceservice.py
index 81835fc8..238012d2 100644
--- a/sugar/presence/presenceservice.py
+++ b/sugar/presence/presenceservice.py
@@ -371,10 +371,14 @@ class PresenceService(gobject.GObject):
         _logger.debug("Error sharing activity %s: %s" % (activity.get_id(), err))
         self.emit("activity-shared", False, None, err)
 
-    def share_activity(self, activity, properties={}):
-        """Ask presence service to ask the activity to share itself
+    def share_activity(self, activity, private=True):
+        """Ask presence service to ask the activity to share itself publicly.
+
+        activity -- sugar.activity.activity.Activity instance
+        private -- bool: True to share by invitation only,
+            False to advertise as shared to everyone.
         
-        Uses the ShareActivity method on the service to ask for the 
+        Uses the AdvertiseActivity method on the service to ask for the 
         sharing of the given activity.  Arranges to emit activity-shared 
         event with:
         
@@ -395,7 +399,8 @@ class PresenceService(gobject.GObject):
 
         atype = activity.get_service_name()
         name = activity.props.title
-        self._ps.ShareActivity(actid, atype, name, properties,
+        # FIXME: Test, then make this AdvertiseActivity:
+        self._ps.ShareActivity(actid, atype, name, private,
                 reply_handler=lambda *args: self._share_activity_cb(activity, *args),
                 error_handler=lambda *args: self._share_activity_error_cb(activity, *args))