Jon Galloway

WordPress feeds offer a choice between Full Text or Summary. The Full Text option is preferable in a lot of cases (e.g. for a podcast), but the feed can grow very large.
One problem with a large feed is that if can exceed the <a href="http://support.google.com/feedburner/bin/answer.py?hl=en&answer=79009" rel="nofollow ugc">Feedburner 512K limit</a>. Your feed may be valid when you first set it up, but eventually when your feed gets big enough, Feedburner will stop updating.
This plugin gives you another setting (available on your Settings / Reading admin page) which sets how many posts should have Full Text. All posts after that will be shown as Summary. This gives you the best of both options – Full Text for new posts, and Summary for older posts. 
<h3>Readme Generator</h3>
This Readme file was generated using <a href='http://sudarmuthu.com/wordpress/wp-readme' rel="nofollow ugc">wp-readme</a>, which generates readme files for WordPress Plugins.

Excerpt Old Posts

This plugin solved my problem with feedbruner.



Greate idea

Shows excerpted content for older posts. This allows more items in the feed while working around the Feedburner 512K feed limit.

Eric Marden

FlareSmith is a plugin to integrate the FeedBurner Stats and FeedFlare services into your WordPress site – all without having to edit any of your theme files!
It acts as a content filter, and adds the required javascript to your site after the output of your original content. It plays well with others (like other content filters), and works quite nicely with the FeedBurner FeedSmith plugin. In fact, I choose the name of my plugin as an homage to FeedSmith.
A FeedBurner account is required to use this plugin.
<h3>Arbitrary section</h3>
The FlareSmith plugin was developed by Eric Marden, and is provided with out warranty under the GPLv3 License. More info and other plugins at: http://xentek.net
Copyright 2008 Eric Marden (email : wp@xentek.net)
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Flare Smith

FlareSmith is a plugin to integrate the FeedBurner Stats and FeedFlare services into your WordPress site - without editing your theme!

Excerpt Old Posts vs Flare Smith