MT（4.2rc）导出的TXT文件里其实是有包含tag和slug数据的， 分别标记为TAGS和BASENAME， 只可惜目前wordpress还不支持，小小patch一下
--- wordpress/wp-admin/import/mt.php 2008-04-15 01:26:07.000000000 +0900
+++ gopherwood.info/wp-admin/import/mt.php 2008-07-01 10:05:56.000000000 +0900
@@ -359,6 +359,16 @@
$category = trim( substr($line, strlen("PRIMARY CATEGORY:")) );
if ( ' != $category )
$post->categories[] = $category;
+ } else if ( 0 === strpos($line, "TAGS:") ) {
+ $tags = trim ( substr($line, strlen("TAGS:")) );
+ if ( ' != $tags ) {
+ $post->post_keywords .= $tags;
+ }
+ } else if ( 0 === strpos($line, "BASENAME:") ) {
+ $slug = trim ( substr($line, strlen("BASENAME:")) );
+ if ( ' != $slug ) {
+ $post->post_name = $slug;
+ }
} else if ( 0 === strpos($line, "DATE:") ) {
$date = trim( substr($line, strlen("DATE:")) );
$date = strtotime($date);