diff --git a/wp-admin/admin-functions.php b/wp-admin/admin-functions.php
index 4f1b0835e..0a50ee0cc 100644
--- a/wp-admin/admin-functions.php
+++ b/wp-admin/admin-functions.php
@@ -647,7 +647,7 @@ function checked( $checked, $current) {
 
 function return_categories_list( $parent = 0 ) {
 	global $wpdb;
-	return $wpdb->get_col( "SELECT cat_ID FROM $wpdb->categories WHERE category_parent = $parent AND ( link_count = 0 OR category_count != 0 OR ( link_count = 0 AND category_count = 0 ) ) ORDER BY category_count DESC" );
+	return $wpdb->get_col( "SELECT cat_ID FROM $wpdb->categories WHERE category_parent = $parent AND ( ( link_count = 0 AND tag_count = 0 ) OR category_count != 0 OR ( link_count = 0 AND category_count = 0 AND tag_count = 0 ) ) ORDER BY category_count DESC" );
 }
 
 function sort_cats( $cat1, $cat2 ) {
@@ -657,6 +657,29 @@ function sort_cats( $cat1, $cat2 ) {
 		return strcasecmp( $cat1['cat_name'], $cat2['cat_name'] );
 }
 
+function get_tags_to_edit( $post_id ) {
+	global $wpdb;
+
+	$post_id = (int) $post_id;
+	if ( !$post_id )
+		return false;
+
+	$tags = $wpdb->get_results( "
+		     SELECT category_id, cat_name
+		     FROM $wpdb->categories, $wpdb->post2cat
+		     WHERE $wpdb->post2cat.category_id = cat_ID AND $wpdb->post2cat.post_id = '$post_id' AND rel_type = 'tag'
+		     " );
+	if ( !$tags )
+		return false;
+
+	foreach ( $tags as $tag )
+		$tag_names[] = $tag->cat_name;
+	$tags_to_edit = join( ', ', $tag_names );
+	$tags_to_edit = attribute_escape( $tags_to_edit );
+	$tags_to_edit = apply_filters( 'tags_to_edit', $tags_to_edit );
+	return $tags_to_edit;
+}
+
 function get_nested_categories( $default = 0, $parent = 0 ) {
 	global $post_ID, $link_id, $mode, $wpdb;
 
@@ -664,7 +687,7 @@ function get_nested_categories( $default = 0, $parent = 0 ) {
 		$checked_categories = $wpdb->get_col( "
 		     SELECT category_id
 		     FROM $wpdb->categories, $wpdb->post2cat
-		     WHERE $wpdb->post2cat.category_id = cat_ID AND $wpdb->post2cat.post_id = '$post_ID'
+		     WHERE $wpdb->post2cat.category_id = cat_ID AND $wpdb->post2cat.post_id = '$post_ID' AND rel_type = 'category'
 		     " );
 
 		if ( count( $checked_categories ) == 0 ) {
@@ -721,7 +744,7 @@ function dropdown_categories( $default = 0 ) {
 
 function return_link_categories_list( $parent = 0 ) {
 	global $wpdb;
-	return $wpdb->get_col( "SELECT cat_ID FROM $wpdb->categories WHERE category_parent = $parent AND ( category_count = 0  OR link_count != 0 OR ( link_count = 0 AND category_count = 0 ) ) ORDER BY link_count DESC" );
+	return $wpdb->get_col( "SELECT cat_ID FROM $wpdb->categories WHERE category_parent = $parent AND ( ( category_count = 0 AND tag_count = 0 ) OR link_count != 0 OR ( link_count = 0 AND category_count = 0 AND tag_count = 0 ) ) ORDER BY link_count DESC" );
 }
 
 function get_nested_link_categories( $default = 0, $parent = 0 ) {
diff --git a/wp-admin/edit-form-advanced.php b/wp-admin/edit-form-advanced.php
index cdf467a47..897222046 100644
--- a/wp-admin/edit-form-advanced.php
+++ b/wp-admin/edit-form-advanced.php
@@ -152,6 +152,9 @@ endforeach;
 <?php echo $form_pingback ?>
 <?php echo $form_prevstatus ?>
 
+<div class="tagdiv"><p>Enter tags (keywords) that you feel describe this post separated by commas: (ex: dogs, san francisco, cats.)<br />
+<input type="text" name="tags_input" id="tags_input" size="30" tabindex="3" value="<?php echo get_tags_to_edit( $post_ID ); ?>" />
+</p></div>
 
 <p class="submit">
 <span id="autosave"></span>
diff --git a/wp-admin/upgrade-schema.php b/wp-admin/upgrade-schema.php
index 77aa8a112..a41ca9479 100644
--- a/wp-admin/upgrade-schema.php
+++ b/wp-admin/upgrade-schema.php
@@ -18,6 +18,7 @@ $wp_queries="CREATE TABLE $wpdb->categories (
   category_parent bigint(20) NOT NULL default '0',
   category_count bigint(20) NOT NULL default '0',
   link_count bigint(20) NOT NULL default '0',
+  tag_count bigint(20) NOT NULL default '0',
   posts_private tinyint(1) NOT NULL default '0',
   links_private tinyint(1) NOT NULL default '0',
   PRIMARY KEY  (cat_ID),
@@ -88,6 +89,7 @@ CREATE TABLE $wpdb->post2cat (
   rel_id bigint(20) NOT NULL auto_increment,
   post_id bigint(20) NOT NULL default '0',
   category_id bigint(20) NOT NULL default '0',
+  rel_type varchar(64) NOT NULL default 'category',
   PRIMARY KEY  (rel_id),
   KEY post_id (post_id,category_id)
 ) $charset_collate;
@@ -389,4 +391,4 @@ function populate_roles_210() {
 	}
 }
 
-?>
+?>
\ No newline at end of file
diff --git a/wp-admin/wp-admin.css b/wp-admin/wp-admin.css
index d65e5eb45..06663866d 100644
--- a/wp-admin/wp-admin.css
+++ b/wp-admin/wp-admin.css
@@ -558,7 +558,7 @@ input.disabled, textarea.disabled {
 	line-height: 140%;
 }
 
-#titlediv input, #guiddiv input {
+#titlediv input, #guiddiv input, #tags_input {
 	margin: 0;
 	width: 100%;
 }
diff --git a/wp-includes/post.php b/wp-includes/post.php
index d74769520..581c9391a 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -517,6 +517,7 @@ function wp_insert_post($postarr = array()) {
 		$post_name       = apply_filters('name_save_pre',      $post_name);
 		$comment_status  = apply_filters('comment_status_pre', $comment_status);
 		$ping_status     = apply_filters('ping_status_pre',    $ping_status);
+		$tags_input      = apply_filters('tags_input_pre',     $tags_input);
 	}
 
 	if ( ('' == $post_content) && ('' == $post_title) && ('' == $post_excerpt) )
@@ -651,7 +652,8 @@ function wp_insert_post($postarr = array()) {
 		$wpdb->query( "UPDATE $wpdb->posts SET post_name = '$post_name' WHERE ID = '$post_ID'" );
 	}
 
-	wp_set_post_categories($post_ID, $post_category);
+	wp_set_post_categories( $post_ID, $post_category );
+	wp_set_post_tags( $post_ID, $tags_input );
 
 	if ( 'page' == $post_type ) {
 		clean_page_cache($post_ID);
@@ -769,6 +771,76 @@ function wp_publish_post($post_id) {
 	return wp_update_post(array('post_status' => 'publish', 'ID' => $post_id, 'no_filter' => true));
 }
 
+function wp_set_post_tags( $post_id = 0, $tags = '' ) {
+	global $wpdb;
+	
+	$post_id = (int) $post_id;
+	
+	if ( !$post_id )
+		return false;
+
+	$tags = explode( ',', $tags );
+	foreach ( $tags as $tag ) {
+		$tag = trim( $tag );
+		if ( !$tag_slug = sanitize_title( $tag ) )
+			continue; // discard
+		if ( !$tag_id = category_exists( $tag ) )
+			$tag_id = wp_create_category( $tag );
+		$tag_ids[] = $tag_id;
+	}
+
+	$tag_ids = array_unique( $tag_ids );
+
+	// First the old tags
+	$old_tags = $wpdb->get_col("
+		SELECT category_id
+		FROM $wpdb->post2cat
+		WHERE post_id = '$post_id' AND rel_type = 'tag'");
+
+	if ( !$old_tags ) {
+		$old_tags = array();
+	} else {
+		$old_tags = array_unique( $old_tags );
+	}
+
+	// Delete any?
+	$delete_tags = array_diff( $old_tags, $tag_ids);
+	if ( $delete_tags ) {
+		foreach ( $delete_tags as $del ) {
+			$wpdb->query("
+				DELETE FROM $wpdb->post2cat
+				WHERE category_id = '$del'
+					AND post_id = '$post_id'
+					AND rel_type = 'tag'
+				");
+		}
+	}
+
+	// Add any?
+	$add_tags = array_diff( $tag_ids, $old_tags );
+	if ( $add_tags ) {
+		foreach ( $add_tags as $new_tag ) {
+			$new_tag = (int) $new_tag;
+			if ( !empty($new_tag) )
+				$wpdb->query("
+					INSERT INTO $wpdb->post2cat (post_id, category_id, rel_type) 
+					VALUES ('$post_id', '$new_tag', 'tag')");
+		}
+	}
+
+	// Update category counts.
+	$all_affected_tags = array_unique( array_merge( $tag_ids, $old_tags ) );
+	foreach ( $all_affected_tags as $tag_id ) {
+		$count = $wpdb->get_var( "SELECT COUNT(*) FROM $wpdb->post2cat, $wpdb->posts WHERE $wpdb->posts.ID=$wpdb->post2cat.post_id AND post_status = 'publish' AND post_type = 'post' AND category_id = '$tag_id' AND rel_type = 'tag'" );
+		$wpdb->query( "UPDATE $wpdb->categories SET tag_count = '$count' WHERE cat_ID = '$tag_id'" );
+		if ( $count == 0 )
+			$wpdb->query( "UPDATE $wpdb->categories SET tag_count = '-1' WHERE cat_ID = '$tag_id'" );
+		clean_category_cache( $tag_id );
+		do_action( 'edit_category', $tag_id );
+		do_action( 'edit_tag', $tag_id );
+	}
+}
+
 function wp_set_post_categories($post_ID = 0, $post_categories = array()) {
 	global $wpdb;
 
@@ -783,7 +855,7 @@ function wp_set_post_categories($post_ID = 0, $post_categories = array()) {
 	$old_categories = $wpdb->get_col("
 		SELECT category_id
 		FROM $wpdb->post2cat
-		WHERE post_id = '$post_ID'");
+		WHERE post_id = '$post_ID' AND rel_type = 'category'");
 
 	if (!$old_categories) {
 		$old_categories = array();
@@ -820,7 +892,7 @@ function wp_set_post_categories($post_ID = 0, $post_categories = array()) {
 	// Update category counts.
 	$all_affected_cats = array_unique(array_merge($post_categories, $old_categories));
 	foreach ( $all_affected_cats as $cat_id ) {
-		$count = $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->post2cat, $wpdb->posts WHERE $wpdb->posts.ID=$wpdb->post2cat.post_id AND post_status = 'publish' AND post_type = 'post' AND category_id = '$cat_id'");
+		$count = $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->post2cat, $wpdb->posts WHERE $wpdb->posts.ID=$wpdb->post2cat.post_id AND post_status = 'publish' AND post_type = 'post' AND category_id = '$cat_id' AND rel_type = 'category'");
 		$wpdb->query("UPDATE $wpdb->categories SET category_count = '$count' WHERE cat_ID = '$cat_id'");
 		clean_category_cache($cat_id);
 		do_action('edit_category', $cat_id);
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 929e2f37c..860f99eb7 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -3,6 +3,6 @@
 // This holds the version number in a separate file so we can bump it without cluttering the SVN
 
 $wp_version = '2.2-bleeding';
-$wp_db_version = 4860;
+$wp_db_version = 4865;
 
 ?>