diff --git a/sugar/activity/activity.py b/sugar/activity/activity.py
index ccc8b90d..3f782b51 100644
--- a/sugar/activity/activity.py
+++ b/sugar/activity/activity.py
@@ -469,13 +469,22 @@ 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=private)
 
     def _realize_cb(self, window):
         wm.set_bundle_id(window.window, self.get_service_name())
diff --git a/sugar/presence/activity.py b/sugar/presence/activity.py
index 2df8793d..bdfc74f5 100644
--- a/sugar/presence/activity.py
+++ b/sugar/presence/activity.py
@@ -167,16 +167,17 @@ class Activity(gobject.GObject):
         return bus_name, connection, channels
 
     def _leave_cb(self):
-        # XXX Is this the right thing to do?
+        """Callback for async action of leaving shared activity."""
         self.emit("joined", False, "left activity")
 
     def _leave_error_cb(self, err):
-        # XXX We are closing down anyway
+        """Callback for error in async leaving of shared activity.
+
+        XXX Add logging!"""
         pass
 
     def leave(self):
         """Leave this shared activity"""
-        # FIXME
         self._joined = False
         self._activity.Leave(reply_handler=self._leave_cb,
                              error_handler=self._leave_error_cb)
diff --git a/sugar/presence/presenceservice.py b/sugar/presence/presenceservice.py
index 9e39a35b..a2712823 100644
--- a/sugar/presence/presenceservice.py
+++ b/sugar/presence/presenceservice.py
@@ -364,7 +364,11 @@ class PresenceService(gobject.GObject):
         return self._new_object(owner_op)
 
     def _share_activity_cb(self, activity, op):
-        """Notify with GObject event of successful sharing of activity"""
+        """Notify with GObject event of successful sharing of activity
+        
+        op -- full dbus path of the new object, must be
+            prefixed with either of _PS_BUDDY_OP or _PS_ACTIVITY_OP
+        """
         psact = self._new_object(op)
         psact._joined = True
         self.emit("activity-shared", True, psact, None)
@@ -374,10 +378,10 @@ 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, properties={}, private=True):
+        """Ask presence service to ask the activity to share itself publicly.
         
-        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:
         
@@ -388,19 +392,33 @@ class PresenceService(gobject.GObject):
         returns None
         """
         actid = activity.get_id()
+        _logger.debug('XXXX in share_activity')
 
         # Ensure the activity is not already shared/joined
         for obj in self._objcache.values():
             if not isinstance(object, Activity):
                 continue
             if obj.props.id == actid or obj.props.joined:
-                raise RuntimeError("Activity %s is already shared." % actid)
+                raise RuntimeError("Activity %s is already shared." %
+                                   actid)
 
         atype = activity.get_service_name()
         name = activity.props.title
-        self._ps.ShareActivity(actid, atype, name, properties,
-                reply_handler=lambda *args: self._share_activity_cb(activity, *args),
-                error_handler=lambda *args: self._share_activity_error_cb(activity, *args))
+        if private:
+            _logger.debug('XXXX private, so calling InviteActivity')
+            self._ps.InviteActivity(actid, atype, name, properties,
+                    reply_handler=lambda *args: \
+                        self._share_activity_cb(activity, *args),
+                    error_handler=lambda *args: \
+                        self._share_activity_error_cb(activity, *args))
+        else:
+            # FIXME: Test, then make this AdvertiseActivity:
+            _logger.debug('XXXX not private, so calling ShareActivity')
+            self._ps.ShareActivity(actid, atype, name, properties,
+                    reply_handler=lambda *args: \
+                        self._share_activity_cb(activity, *args),
+                    error_handler=lambda *args: \
+                        self._share_activity_error_cb(activity, *args))
 
     def get_preferred_connection(self):
         """Gets the preferred telepathy connection object that an activity