たとえばShrookはRSSの302 Movedに追従するよ

# curl --dump-header h http://rss.itmedia.co.jp/rss/2.0/ep_opensource.xml

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">

<html><head>

<title>302 Found</title>

</head><body>

<h1>Found</h1>

<p>The document has moved <a href="http://rss.rssad.jp/rss/itm/2.0/ep_opensource.xml">here</a>.</p>

</body></html>

# cat h

HTTP/1.0 302 Moved Temporarily

Date: Fri, 02 Nov 2007 16:02:15 GMT

Server: Apache

Location: http://rss.rssad.jp/rss/itm/2.0/ep_opensource.xml

Content-Type: text/html; charset=iso-8859-1

Via: 1.1 AN-0016020114351545

X-Cache: MISS from sq02.itmedia.co.jp

Content-Length: 233

Connection: Keep-alive

Via: 1.1 AN-0016020114351545