diff --git a/README b/README
index 74ef138a2a32f6302c50f43ae1b0193e5b703bb3..f5a0e27cc54873e752448a02f22498342ad41160 100644
--- a/README
+++ b/README
@@ -1496,8 +1496,9 @@ Configuration options specific to notices.
 contentlimit: max length of the plain-text content of a notice.
     Default is null, meaning to use the site-wide text limit.
     0 means no limit.
-defaultscope: default scope for notices. Defaults to 0; set to
-	      1 to keep notices private to this site by default.
+defaultscope: default scope for notices. If null, the default
+	scope depends on site/private. It's 1 if the site is private,
+	0 otherwise. Set this value to override.
 
 message
 -------
diff --git a/classes/Notice.php b/classes/Notice.php
index 87363158dd7bd9353ed06b07f27f087d1ec84488..29824ab700587eef371e1737d834914c2f332dd3 100644
--- a/classes/Notice.php
+++ b/classes/Notice.php
@@ -448,7 +448,7 @@ class Notice extends Memcached_DataObject
             if (!empty($reply)) {
                 $notice->scope = $reply->scope;
             } else {
-                $notice->scope = common_config('notice', 'defaultscope');
+                $notice->scope = self::defaultScope();
             }
         } else {
             $notice->scope = $scope;
@@ -2469,5 +2469,18 @@ class Notice extends Memcached_DataObject
         $skip = array('_original', '_profile');
         return array_diff($vars, $skip);
     }
+    
+    static function defaultScope()
+    {
+    	$scope = common_config('notice', 'defaultscope');
+    	if (is_null($scope)) {
+    		if (common_config('site', 'private')) {
+    			$scope = 1;
+    		} else {
+    			$scope = 0;
+    		}
+    	}
+    	return $scope;
+    }
 
 }
diff --git a/lib/default.php b/lib/default.php
index 938716b3a4361cda496a94946eae67fa8ef444e0..4a7d6110c5c95c5c648becf63e5655e7cdb6c44a 100644
--- a/lib/default.php
+++ b/lib/default.php
@@ -288,7 +288,7 @@ $default =
               'gc_limit' => 1000), // max sessions to expire at a time
         'notice' =>
         array('contentlimit' => null,
-              'defaultscope' => 0), // set to 0 for default open
+              'defaultscope' => null), // null means 1 if site/private, 0 otherwise
         'message' =>
         array('contentlimit' => null),
         'location' =>
diff --git a/scripts/createsim.php b/scripts/createsim.php
index 14790aa8f39467751de56409c383876cb23652be..e3677e1564bda25293619f7acb4b2299b61aefd7 100644
--- a/scripts/createsim.php
+++ b/scripts/createsim.php
@@ -72,7 +72,7 @@ function newNotice($i, $tagmax)
 {
     global $userprefix;
 
-    $options = array('scope' => common_config('notice', 'defaultscope'));
+    $options = array('scope' => Notice::defaultScope());
 
     $n = rand(0, $i - 1);
     $user = User::staticGet('nickname', sprintf('%s%d', $userprefix, $n));