diff --git a/timeago.install b/timeago.install
index 42210b2..86522b9 100644
--- a/timeago.install
+++ b/timeago.install
@@ -15,6 +15,13 @@ if (!defined('TIMEAGO_LIBRARY_DOWNLOAD_URL')) {
 }
 
 /**
+ * Implements hook_install().
+ */ 
+function timeago_install() {
+  variable_set('date_format_time_ago_dynamic', TIMEAGO_FORMAT_MEDIUM_US);
+}
+
+/**
  * Implements hook_requirements().
  */
 function timeago_requirements($phase) {
@@ -125,4 +132,5 @@ function timeago_uninstall() {
   variable_del('timeago_node');
   variable_del('timeago_comment');
   variable_del('timeago_elem');
+  variable_del('date_format_time_ago_dynamic');
 }
diff --git a/timeago.module b/timeago.module
index 8dd4ed0..2a6b120 100644
--- a/timeago.module
+++ b/timeago.module
@@ -180,6 +180,15 @@ function timeago_date_formats() {
 }
 
 /**
+ * Implements hook_date_format_types().
+ */
+function timeago_date_format_types() {
+   return array(
+    'time_ago_dynamic' => t('Time ago (dynamically updating)'), 
+  );
+}
+
+/**
  * Implements hook_init().
  */
 function timeago_init() {