Index: wp-admin/includes/import.php
===================================================================
--- wp-admin/includes/import.php	(revision 22599)
+++ wp-admin/includes/import.php	(working copy)
@@ -93,3 +93,93 @@
 
 	return array( 'file' => $file, 'id' => $id );
 }
+
+/**
+ * Returns a list from WordPress.org of popular importer plugins.
+ *
+ * @since 3.5.0
+ *
+ * @return array Importers with metadata for each.
+ */
+function wp_get_popular_importers() {
+	include ABSPATH . WPINC . '/version.php'; // include an unmodified $wp_version
+
+	$locale = get_locale();
+	$popular_importers = get_site_transient( 'popular_importers_' . $locale );
+
+	if ( ! $popular_importers ) {
+		$url = add_query_arg( 'locale', get_locale(), 'http://api.wordpress.org/core/importers/1.0/' );
+		$options = array( 'user-agent' => 'WordPress/' . $wp_version . '; ' . home_url() );
+		$popular_importers = maybe_unserialize( wp_remote_retrieve_body( wp_remote_get( $url, $options ) ) );
+
+		if ( is_array( $popular_importers ) )
+			set_site_transient( 'popular_importers_' . $locale, $popular_importers, 2 * DAY_IN_SECONDS );
+		else
+			$popular_importers = false;
+	}
+
+	if ( is_array( $popular_importers ) ) {
+		// If the data was received as translated, return it as-is.
+		if ( $popular_importers['translated'] )
+			return $popular_importers['importers'];
+
+		foreach ( $popular_importers['importers'] as &$importer ) {
+			$importer['description'] = translate( $importer['description'] );
+			if ( $importer['name'] != 'WordPress' )
+				$importer['name'] = translate( $importer['name'] );
+		}
+		return $popular_importers['importers'];
+	}
+
+	return array(
+		// slug => name, description, plugin slug, and register_importer() slug
+		'blogger' => array(
+			'name' => __( 'Blogger' ),
+			'description' => __( 'Install the Blogger importer to import posts, comments, and users from a Blogger blog.' ),
+			'plugin-slug' => 'blogger-importer',
+			'importer-id' => 'blogger',
+		),
+		'wpcat2tag' => array(
+			'name' => __( 'Categories and Tags Converter' ),
+			'description' => __( 'Install the category/tag converter to convert existing categories to tags or tags to categories, selectively.' ),
+			'plugin-slug' => 'wpcat2tag-importer',
+			'importer-id' => 'wp-cat2tag',
+		),
+		'livejournal' => array(
+			'name' => __( 'LiveJournal' ),
+			'description' => __( 'Install the LiveJournal importer to import posts from LiveJournal using their API.' ),
+			'plugin-slug' => 'livejournal-importer',
+			'importer-id' => 'livejournal',
+		),
+		'movabletype' => array(
+			'name' => __( 'Movable Type and TypePad' ),
+			'description' => __( 'Install the Movable Type importer to import posts and comments from a Movable Type or TypePad blog.' ),
+			'plugin-slug' => 'movabletype-importer',
+			'importer-id' => 'mt',
+		),
+		'opml' => array(
+			'name' => __( 'Blogroll' ),
+			'description' => __( 'Install the blogroll importer to import links in OPML format.' ),
+			'plugin-slug' => 'opml-importer',
+			'importer-id' => 'opml',
+		),
+		'rss' => array(
+			'name' => __( 'RSS' ),
+			'description' => __( 'Install the RSS importer to import posts from an RSS feed.' ),
+			'plugin-slug' => 'rss-importer',
+			'importer-id' => 'rss',
+		),
+		'tumblr' => array(
+			'name' => __( 'Tumblr' ),
+			'description' => __( 'Install the Tumblr importer to import posts &amp; media from Tumblr using their API.' ),
+			'plugin-slug' => 'tumblr-importer',
+			'importer-id' => 'tumblr',
+		),
+		'wordpress' => array(
+			'name' => 'WordPress',
+			'description' => __( 'Install the WordPress importer to import posts, pages, comments, custom fields, categories, and tags from a WordPress export file.' ),
+			'plugin-slug' => 'wordpress-importer',
+			'importer-id' => 'wordpress',
+		),
+	);
+}
Index: wp-admin/import.php
===================================================================
--- wp-admin/import.php	(revision 22599)
+++ wp-admin/import.php	(working copy)
@@ -29,22 +29,19 @@
 	'<p>' . __('<a href="http://wordpress.org/support/" target="_blank">Support Forums</a>') . '</p>'
 );
 
-$popular_importers = array();
-if ( current_user_can('install_plugins') )
-	$popular_importers = array(
-		'blogger' => array( __('Blogger'), __('Install the Blogger importer to import posts, comments, and users from a Blogger blog.'), 'install' ),
-		'wpcat2tag' => array(__('Categories and Tags Converter'), __('Install the category/tag converter to convert existing categories to tags or tags to categories, selectively.'), 'install', 'wp-cat2tag' ),
-		'livejournal' => array( __( 'LiveJournal' ), __( 'Install the LiveJournal importer to import posts from LiveJournal using their API.' ), 'install' ),
-		'movabletype' => array( __('Movable Type and TypePad'), __('Install the Movable Type importer to import posts and comments from a Movable Type or TypePad blog.'), 'install', 'mt' ),
-		'opml' => array( __('Blogroll'), __('Install the blogroll importer to import links in OPML format.'), 'install' ),
-		'rss' => array( __('RSS'), __('Install the RSS importer to import posts from an RSS feed.'), 'install' ),
-		'tumblr' => array( __('Tumblr'), __('Install the Tumblr importer to import posts &amp; media from Tumblr using their API.'), 'install' ),
-		'wordpress' => array( 'WordPress', __('Install the WordPress importer to import posts, pages, comments, custom fields, categories, and tags from a WordPress export file.'), 'install' )
-	);
+if ( current_user_can( 'install_plugins' ) )
+	$popular_importers = wp_get_popular_importers();
+else
+	$popular_importers = array();
 
-if ( ! empty( $_GET['invalid'] ) && !empty($popular_importers[$_GET['invalid']][3]) ) {
-	wp_redirect( admin_url('import.php?import=' . $popular_importers[$_GET['invalid']][3]) );
-	exit;
+// Detect and redirect invalid importers like 'movabletype', which is registered as 'mt'
+if ( ! empty( $_GET['invalid'] ) && isset( $popular_importers[ $_GET['invalid'] ] ) ) {
+	$importer_id = $popular_importers[ $_GET['invalid'] ]['importer-id'];
+	if ( $importer_id != $_GET['invalid'] ) { // Prevent redirect loops.
+		wp_redirect( admin_url( 'admin.php?import=' . $importer_id ) );
+		exit;
+	}
+	unset( $importer_id );
 }
 
 add_thickbox();
@@ -68,28 +65,26 @@
 
 // If a popular importer is not registered, create a dummy registration that links to the plugin installer.
 foreach ( $popular_importers as $pop_importer => $pop_data ) {
-	if ( isset( $importers[$pop_importer] ) )
+	if ( isset( $importers[ $pop_importer ] ) )
 		continue;
-	if ( isset( $pop_data[3] ) && isset( $importers[ $pop_data[3] ] ) )
+	if ( isset( $importers[ $pop_data['importer-id'] ] ) )
 		continue;
-
-	$importers[$pop_importer] = $popular_importers[$pop_importer];
+	$importers[ $pop_data['importer-id'] ] = array( $pop_data['name'], $pop_data['description'], 'install' => $pop_data['plugin-slug'] );
 }
 
-if ( empty($importers) ) {
-	echo '<p>'.__('No importers are available.').'</p>'; // TODO: make more helpful
+if ( empty( $importers ) ) {
+	echo '<p>' . __('No importers are available.') . '</p>'; // TODO: make more helpful
 } else {
-	uasort($importers, create_function('$a, $b', 'return strcmp($a[0], $b[0]);'));
+	uasort($importers, create_function('$a, $b', 'return strnatcasecmp($a[0], $b[0]);'));
 ?>
 <table class="widefat importers" cellspacing="0">
 
 <?php
-	$style = '';
-	foreach ($importers as $id => $data) {
-		$style = ('class="alternate"' == $style || 'class="alternate active"' == $style) ? '' : 'alternate';
+	$alt = '';
+	foreach ($importers as $importer_id => $data) {
 		$action = '';
-		if ( 'install' == $data[2] ) {
-			$plugin_slug = $id . '-importer';
+		if ( isset( $data['install'] ) ) {
+			$plugin_slug = $data['install'];
 			if ( file_exists( WP_PLUGIN_DIR . '/' . $plugin_slug ) ) {
 				// Looks like Importer is installed, But not active
 				$plugins = get_plugins( '/' . $plugin_slug );
@@ -111,13 +106,12 @@
 				}
 			}
 		} else {
-			$action = "<a href='" . esc_url("admin.php?import=$id") . "' title='" . esc_attr( wptexturize(strip_tags($data[1])) ) ."'>{$data[0]}</a>";
+			$action = "<a href='" . esc_url( "admin.php?import=$importer_id" ) . "' title='" . esc_attr( wptexturize( strip_tags( $data[1] ) ) ) ."'>{$data[0]}</a>";
 		}
 
-		if ($style != '')
-			$style = 'class="'.$style.'"';
+		$alt = $alt ? '' : ' class="alternate"';
 		echo "
-			<tr $style>
+			<tr$alt>
 				<td class='import-system row-title'>$action</td>
 				<td class='desc'>{$data[1]}</td>
 			</tr>";
