diff --git a/docs/NEWS b/docs/NEWS
index 820587b9..0cc0bd45 100644
--- a/docs/NEWS
+++ b/docs/NEWS
@@ -3,6 +3,13 @@
 Version 1.6 ()
 ------------------------------------------------------------------------
 
+    * Added ability to mark authorgroups as "hidden", so that members
+      of such groups are excluded from common author listings.
+      (Ref http://board.s9y.org/viewtopic.php?f=11&t=16237)
+      (garvinhicking)
+      
+    * Added option for SMF importer to also import tags
+
     * Added experimental global variable $i18n_filename_utf8 that can
       be set in a serendipity_config_local.inc.php or language include
       file, which will return Unicode-Permalinks.
@@ -11,7 +18,7 @@ Version 1.6 ()
     * Added event hook backend_sendcomment for sending comments and
       being able to chang via plugin API (onli)
 
-Version 1.5.1 ()
+Version 1.5.1 (December 21st, 2009)
 ------------------------------------------------------------------------
 
     * Fix bug with not showing "html" type configuration items.
diff --git a/include/admin/entries.inc.php b/include/admin/entries.inc.php
index 43fb596a..f0f04acd 100644
--- a/include/admin/entries.inc.php
+++ b/include/admin/entries.inc.php
@@ -113,7 +113,7 @@ function serendipity_drawList() {
                 <select name="serendipity[filter][author]">
                     <option value="">--</option>
 <?php
-                    $users = serendipity_fetchUsers('', null, true);
+                    $users = serendipity_fetchUsers('', 'hidden', true);
                     if (is_array($users)) {
                         foreach ($users AS $user) {
                             if (isset($user['artcount']) && $user['artcount'] < 1) continue;
diff --git a/include/admin/groups.inc.php b/include/admin/groups.inc.php
index b77dcdd4..0c9a566e 100644
--- a/include/admin/groups.inc.php
+++ b/include/admin/groups.inc.php
@@ -163,7 +163,7 @@ foreach($allusers AS $user) {
             $permname = $perm;
         }
 
-        if (!serendipity_checkPermission($perm)) {
+        if (!serendipity_checkPermission($perm) && $perm != 'hiddenGroup') {
             echo "<tr>\n";
             echo "<td>$indent" . htmlspecialchars($permname) . "</td>\n";
             echo '<td>' . $indentB . ' ' . (!empty($selected) ? YES : NO) . '</td>' . "\n";
diff --git a/include/functions.inc.php b/include/functions.inc.php
index ce96a5d4..f8a890b3 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -405,7 +405,12 @@ function serendipity_fetchUsers($user = '', $group = null, $is_count = false) {
                                $query_group
                       ORDER BY a.realname ASC";
     } else {
-        if (is_array($group)) {
+
+        if ($group === 'hidden') {
+            $query_join .= "LEFT OUTER JOIN {$serendipity['dbPrefix']}groupconfig AS gc
+                                         ON (gc.property = 'hiddenGroup' AND gc.id = ag.groupid AND gc.value = 'true')";
+            $where .= " AND ISNULL(gc.id) ";
+        } elseif (is_array($group)) {
             foreach($group AS $idx => $groupid) {
                 $group[$idx] = (int)$groupid;
             }
@@ -432,7 +437,7 @@ function serendipity_fetchUsers($user = '', $group = null, $is_count = false) {
                LEFT OUTER JOIN {$serendipity['dbPrefix']}groups AS g
                             ON ag.groupid  = g.id
                                $query_join
-                         WHERE g.id IN ($group_sql)
+                         WHERE " . ($group_sql ? "g.id IN ($group_sql)" : '1=1') . "
                                $where
                                $query_group
                       ORDER BY a.realname ASC";
diff --git a/include/functions_config.inc.php b/include/functions_config.inc.php
index 257724ce..2569bbcd 100644
--- a/include/functions_config.inc.php
+++ b/include/functions_config.inc.php
@@ -1153,6 +1153,9 @@ function serendipity_getPermissionNames() {
 
         'adminTemplates'
             => array(USERLEVEL_ADMIN, USERLEVEL_CHIEF),
+
+        'hiddenGroup'
+            => array(-1)
     );
 }
 
@@ -1574,7 +1577,7 @@ function serendipity_updateGroupConfig($groupid, &$perms, &$values, $isNewPriv =
             $value = 'false';
         }
 
-        if ($isNewPriv == false && !serendipity_checkPermission($perm)) {
+        if ($isNewPriv == false && !serendipity_checkPermission($perm) && $perm != 'hiddenGroup') {
             if (!isset($storage[$perm])) {
                 $value = 'false';
             } else {
diff --git a/include/functions_plugins_admin.inc.php b/include/functions_plugins_admin.inc.php
index 3dc59e5c..2517cfa7 100644
--- a/include/functions_plugins_admin.inc.php
+++ b/include/functions_plugins_admin.inc.php
@@ -269,7 +269,7 @@ function ownership($authorid, $name, $is_plugin_owner = false) {
 
     static $users = array();
     if (empty($users)) {
-        $users = serendipity_fetchUsers();
+        $users = serendipity_fetchUsers('', 'hidden');
     }
 
     if ($is_plugin_owner) {
diff --git a/include/plugin_internal.inc.php b/include/plugin_internal.inc.php
index 648e3652..1a82bbf4 100644
--- a/include/plugin_internal.inc.php
+++ b/include/plugin_internal.inc.php
@@ -1804,7 +1804,7 @@ class serendipity_authors_plugin extends serendipity_plugin {
         $is_form  = serendipity_db_bool($this->get_config('allow_select'));
         $is_count = serendipity_db_bool($this->get_config('showartcount'));
         $mincount = (int)$this->get_config('mincount');
-        $authors  = serendipity_fetchUsers(null, null, $is_count);
+        $authors  = serendipity_fetchUsers(null, 'hidden', $is_count);
         $html       = '';
 
         if ($is_form) {
diff --git a/plugins/serendipity_event_entryproperties/serendipity_event_entryproperties.php b/plugins/serendipity_event_entryproperties/serendipity_event_entryproperties.php
index 2b91303f..5b1100ef 100644
--- a/plugins/serendipity_event_entryproperties/serendipity_event_entryproperties.php
+++ b/plugins/serendipity_event_entryproperties/serendipity_event_entryproperties.php
@@ -149,7 +149,7 @@ class serendipity_event_entryproperties extends serendipity_event
         global $serendipity;
 
         if (serendipity_checkPermission('adminUsersMaintainOthers')) {
-            $users = serendipity_fetchUsers('');
+            $users = serendipity_fetchUsers('', 'hidden');
         } elseif (serendipity_checkPermission('adminUsersMaintainSame')) {
             $users = serendipity_fetchUsers('', serendipity_getGroups($serendipity['authorid'], true));
         } else {
@@ -348,7 +348,7 @@ class serendipity_event_entryproperties extends serendipity_event
             <br /><?php echo PERM_READ . ': <em>'. AUTHOR . '</em>'; ?><br />
             <select class="entryproperties_access_users" onchange="document.getElementById('properties_access_member').checked = true;" style="margin-left: 5px" multiple="multiple" name="serendipity[properties][access_users][]" size="4">
 <?php
-                $users = serendipity_fetchUsers();
+                $users = serendipity_fetchUsers('', 'hidden');
                 foreach($users AS $user) {
 ?>
                 <option value="<?php echo $user['authorid']; ?>" <?php echo (in_array($user['authorid'], $access_users) ? 'selected="selected"' : ''); ?>><?php echo htmlspecialchars($user['realname']); ?></option>