Index: trunk/wp-includes/category-template.php
===================================================================
--- trunk/wp-includes/category-template.php	(revision 10896)
+++ trunk/wp-includes/category-template.php	(working copy)
@@ -293,11 +293,7 @@
  * @return string Category description, available.
  */
 function category_description( $category = 0 ) {
-	global $cat;
-	if ( !$category )
-		$category = $cat;
-
-	return get_term_field( 'description', $category, 'category' );
+	return term_description( $category, 'category' );
 }
 
 /**
@@ -799,6 +795,36 @@
 }
 
 /**
+ * Retrieve tag description.
+ *
+ * @since 2.9
+ *
+ * @param int $tag Optional. Tag ID. Will use global tag ID by default.
+ * @return string Tag description, available.
+ */
+function tag_description( $tag = 0 ) {
+	return term_description( $tag );
+}
+
+/**
+ * Retrieve term description.
+ *
+ * @since 2.9
+ *
+ * @param int $term Optional. Term ID. Will use global term ID by default.
+ * @return string Term description, available.
+ */
+function term_description( $term = 0, $taxonomy = 'post_tag' ) {
+	if ( !$term && ( is_tax() || is_tag() || is_category() ) ) {
+		global $wp_query;
+		$term = $wp_query->get_queried_object();
+		$taxonomy = $term->taxonomy;
+		$term = $term->term_id;
+	}
+	return get_term_field( 'description', $term, $taxonomy );
+}
+
+/**
  * Retrieve the terms of the taxonomy that are attached to the post.
  *
  * This function can only be used within the loop.
Index: trunk/wp-admin/admin-ajax.php
===================================================================
--- trunk/wp-admin/admin-ajax.php	(revision 10896)
+++ trunk/wp-admin/admin-ajax.php	(working copy)
@@ -1169,6 +1169,9 @@
 			else
 				$taxonomy = 'post_tag';
 
+			$tag = get_term( $id, $taxonomy );
+			$_POST['description'] = $tag->description;
+
 			$updated = wp_update_term($id, $taxonomy, $_POST);
 			if ( $updated && !is_wp_error($updated) ) {
 				$tag = get_term( $updated['term_id'], $taxonomy );
Index: trunk/wp-admin/includes/template.php
===================================================================
--- trunk/wp-admin/includes/template.php	(revision 10896)
+++ trunk/wp-admin/includes/template.php	(working copy)
@@ -668,6 +668,9 @@
 					$out .= '<div class="name">' . $qe_data->name . '</div>';
 					$out .= '<div class="slug">' . $qe_data->slug . '</div></div></td>';
 					break;
+				case 'description':
+					$out .= "<td $attributes>$tag->description</td>";
+					break;
 				case 'slug':
 					$out .= "<td $attributes>$tag->slug</td>";
 					break;
@@ -872,6 +875,7 @@
 			$_wp_column_headers[$page] = array(
 				'cb' => '<input type="checkbox" />',
 				'name' => __('Name'),
+				'description' => __('Description'),
 				'slug' => __('Slug'),
 				'posts' => __('Posts')
 			);
Index: trunk/wp-admin/edit-tags.php
===================================================================
--- trunk/wp-admin/edit-tags.php	(revision 10896)
+++ trunk/wp-admin/edit-tags.php	(working copy)
@@ -287,6 +287,12 @@
 	<p><?php _e('The &#8220;slug&#8221; is the URL-friendly version of the name. It is usually all lowercase and contains only letters, numbers, and hyphens.'); ?></p>
 </div>
 
+<div class="form-field">
+	<label for="description"><?php _e('Description') ?></label>
+	<textarea name="description" id="description" rows="5" cols="40"></textarea>
+    <p><?php _e('The description is not prominent by default, however some themes may show it.'); ?></p>
+</div>
+
 <p class="submit"><input type="submit" class="button" name="submit" value="<?php _e('Add Tag'); ?>" /></p>
 <?php do_action('add_tag_form'); ?>
 </form></div>
Index: trunk/wp-admin/edit-tag-form.php
===================================================================
--- trunk/wp-admin/edit-tag-form.php	(revision 10896)
+++ trunk/wp-admin/edit-tag-form.php	(working copy)
@@ -34,6 +34,11 @@
 			<td><input name="slug" id="slug" type="text" value="<?php if ( isset( $tag->slug ) ) echo attribute_escape(apply_filters('editable_slug', $tag->slug)); ?>" size="40" />
             <p><?php _e('The &#8220;slug&#8221; is the URL-friendly version of the name. It is usually all lowercase and contains only letters, numbers, and hyphens.'); ?></p></td>
 		</tr>
+		<tr class="form-field">
+			<th scope="row" valign="top"><label for="description"><?php _e('Description') ?></label></th>
+			<td><textarea name="description" id="description" rows="5" cols="50" style="width: 97%;"><?php echo wp_specialchars($tag->description); ?></textarea><br />
+            <?php _e('The description is not prominent by default, however some themes may show it.'); ?></td>
+		</tr>
 	</table>
 <p class="submit"><input type="submit" class="button-primary" name="submit" value="<?php _e('Update Tag'); ?>" /></p>
 <?php do_action('edit_tag_form', $tag); ?>