RSS 2.0形式に…

<rss version="2.0" xmlns:coop="<a href="http://www.google.com/coop/namespace">">http://www.google.com/coop/namespace"></a>
<coop:keyword>

…を追加。

例:

<?xml version="1.0"?>

<rss version="2.0" xmlns:coop="<a href="http://www.google.com/coop/namespace">">http://www.google.com/coop/namespace"></a>

	<channel>
	<title>Google Sample Channel</title>
	<link><a href="http://www.google.com/coop</link>">http://www.google.com/coop</link></a>
	<description>Enhance Your Search</description>

	<item>
		<author>Google</author>
		<coop:keyword>Subscribed Links Guide</coop:keyword>
		<title>Guide for Developers</title>
		<link><a href="http://www.google.com/coop/docs/index.html</link>">http://www.google.com/coop/docs/index.html</link></a>

		<description>
		Learn more about how to create custom 
		subscribed links.
		</description>
	</item>

	</channel>
</rss>