Why Does my RSS Feed Max Out At 1000?

<?xml version="1.0"?>
<rss version="2.0">
<channel>
 
<title>The title of my RSS 2.0 Feed</title>
<link>http://www.example.com/</link>
<description>This is my rss 2 feed description</description>
<lastBuildDate>Mon, 12 Sep 2005 18:37:00 GMT</lastBuildDate>
<language>en-us</language>
 
<item>
<title>Title of an item</title>
<link>http://example.com/item/123</link>
<guid>http://example.com/item/123</guid>
<pubDate>Mon, 12 Sep 2005 18:37:00 GMT</pubDate>
<description>[CDATA[ This is the description. ]]</description>
</item>
 

<item>
<title>Title of an item</title>
<link>http://example.com/item/123</link>
<guid>http://example.com/item/123</guid>
<pubDate>Mon, 12 Sep 2005 18:37:00 GMT</pubDate>
<description>[CDATA[ This is the description. ]]</description>
</item>
<item>
<title>Title of an item</title>
<link>http://example.com/item/123</link>
<guid>http://example.com/item/123</guid>
<pubDate>Mon, 12 Sep 2005 18:37:00 
GMT</pubDate>
<description>[CDATA[ This is the description. ]]</description>
</item>
 

<item>
<title>Title of an item</title>
<link>http://example.com/item/123</link>
<guid>http://example.com/item/123</guid>
<pubDate>Mon, 12 Sep 2005 18:37:00 GMT</pubDate>
<description>[CDATA[ This 
is the description. ]]</description>
</item>"
 
 

</channel>
</rss>