Index: wp-admin/includes/schema.php
===================================================================
--- wp-admin/includes/schema.php	(revision 31332)
+++ wp-admin/includes/schema.php	(working copy)
@@ -910,7 +910,7 @@
 		$site_admins = get_site_option( 'site_admins' );
 	}
 
-	$welcome_email = __( 'Dear User,
+	$welcome_email = __( 'Howdy USERNAME,
 
 Your new SITE_NAME site has been successfully set up at:
 BLOG_URL