diff --git modules/rdf/rdf.module modules/rdf/rdf.module
index 49ead1e..e550626 100644
--- modules/rdf/rdf.module
+++ modules/rdf/rdf.module
@@ -634,13 +634,11 @@ function theme_rdf_template_variable_wrapper($variables) {
  *     element.
  *
  * @return
- *   A string of HTML containing markup that can be understood by an RDF parser.
+ *   A string of HTML containing markup that can be understood by RDFa parsers.
  *
- * Tip for themers: while this default implementation results in valid markup
- * for the XHTML+RDFa doctype, you may need to override this in your theme to be
- * valid for doctypes that don't support empty spans. Or, if empty spans create
- * visual problems in your theme, you may want to override this to set a
- * class on them, and apply a CSS rule of display:none for that class.
+ * Tip for themers: if empty spans create visual problems in your theme, you may
+ * want to override this to set a class on them, and apply a CSS rule of
+ * display:none for that class.
  *
  * @see rdf_process()
  *
@@ -649,7 +647,7 @@ function theme_rdf_template_variable_wrapper($variables) {
 function theme_rdf_metadata($variables) {
   $output = '';
   foreach ($variables['metadata'] as $attributes) {
-    $output .= '<span' . drupal_attributes($attributes) . ' />';
+    $output .= '<span' . drupal_attributes($attributes) . '></span>';
   }
   return $output;
 }