diff --git a/lib/microappplugin.php b/lib/microappplugin.php
new file mode 100644
index 0000000000..23b4b5bb84
--- /dev/null
+++ b/lib/microappplugin.php
@@ -0,0 +1,70 @@
+<?php
+/**
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2011, StatusNet, Inc.
+ *
+ * Superclass for microapp plugin
+ * 
+ * PHP version 5
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Microapp
+ * @package   StatusNet
+ * @author    Evan Prodromou <evan@status.net>
+ * @copyright 2011 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+if (!defined('STATUSNET')) {
+    // This check helps protect against security problems;
+    // your code file can't be executed directly from the web.
+    exit(1);
+}
+
+/**
+ * Superclass for microapp plugins
+ *
+ * This class lets you define micro-applications with different kinds of activities.
+ *
+ * The applications work more-or-less like other 
+ * 
+ * @category  Microapp
+ * @package   StatusNet
+ * @author    Evan Prodromou <evan@status.net>
+ * @copyright 2011 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+abstract class MicroAppPlugin extends Plugin
+{
+    abstract function types();
+    abstract function saveNoticeFromActivity($activity);
+    abstract function activityFromNotice($notice);
+    abstract function showNotice($notice, $out);
+    abstract function entryForm();
+
+    function isMyNotice($notice) {
+        $types = $this->types();
+        return in_array($notice->object_type, $types);
+    }
+
+    function isMyActivity($activity) {
+        $types = $this->types();
+        return (count($activity->objects) == 1 &&
+                in_array($activity->objects[0]->type, $types));
+    }
+}