Index: functions.php
===================================================================
--- functions.php	(revision 15382)
+++ functions.php	(working copy)
@@ -520,10 +520,13 @@
  * @since Twenty Ten 1.0
  */
 function twentyten_posted_in() {
-	// Retrieves tag list of current post, separated by commas.
+	// Retrieves category and tag lists of current post, separated by commas.
+	$cat_list = get_the_category_list( ', ' );
 	$tag_list = get_the_tag_list( '', ', ' );
-	if ( $tag_list ) {
+	if ( $cat_list && $tag_list ) {
 		$posted_in = __( 'This entry was posted in %1$s and tagged %2$s. Bookmark the <a href="%3$s" title="Permalink to %4$s" rel="bookmark">permalink</a>.', 'twentyten' );
+	} elseif ( $tag_list ) {
+		$posted_in = __( 'This entry was tagged %2$s. Bookmark the <a href="%3$s" title="Permalink to %4$s" rel="bookmark">permalink</a>.', 'twentyten' );
 	} elseif ( is_object_in_taxonomy( get_post_type(), 'category' ) ) {
 		$posted_in = __( 'This entry was posted in %1$s. Bookmark the <a href="%3$s" title="Permalink to %4$s" rel="bookmark">permalink</a>.', 'twentyten' );
 	} else {
@@ -532,7 +535,7 @@
 	// Prints the string, replacing the placeholders.
 	printf(
 		$posted_in,
-		get_the_category_list( ', ' ),
+		$cat_list,
 		$tag_list,
 		get_permalink(),
 		the_title_attribute( 'echo=0' )