该死！2007年2月刚使用了Math Comment Spam Protection 2.0插件，用来抵御垃圾评论。效果非常不错，但这段时间又被垃圾引用弄得很头疼。上网搜了一下。感觉这款叫WP-Hardened-Trackback的反垃圾引用插件不错，现在已安装完成。OK! Bye bye trackback spam!
你可以在这里下载：
Instructions:
copy wp-hardened-trackback.php, getkey.php and htrackback.js into your plugins
directory
create a directory named tbkeys/ in your plugins directory
make it world writable (chmod 777)
use the following template tag to place the trackback box:
REMOVE all old trackback tags from your templates. the ones
that look like must go. These url’s would
confuse the visitor and they will not work anymore anyway.
Activate the pluginYou can edit options under Options -> Hardened Trackback
