Hey, check out the Better Feed WordPress plugin. Better Feed gives you the ability to add extra stuff in your feed. For instance, the footer below appears at the bottom of each post in my feed. You won't see this footer on my blog, but you should be able to see it if you are reading this post from a RSS reader.
Yes, I know you can already insert links with FeedFlares. The difference is that FeedFlares are actually images that link to FeedBurner before they are redirected to your URL. Better Feed links are text links that point directly to your site. So if your site is syndicated elsewhere, you will have real links pointing to your site. Links that can pass PageRank juice to your site.
With this plugin, I can also insert images (ad banners) in my feed. I was even able to get phpAdsNew ad server to serve ads into my feed. I could see two different ad banners in my FeedBurner feed (the one at: feeds.feedburner.com/myfeed). However, the ads are implemented via Javascript, which don't seem to work in RSS readers like Bloglines, Google RSS Reader, and Newsgator.
I love the plugin, but if you don't like playing with HTML code, the plugin isn't for you. There is no admin interface. You have to edit the plugin file itself. It isn't hard. For instance, I added the HTML code below to the plugin file for my RSS feed footer:
<hr noshade style="margin:0;height:1px" />
<p align="center">Permalink: <a href="%%posturl%%">%%posttitle%%</a><br />Links: <a href="http://izachy.com/">iZachy</a> : : <a href="http://daddyforever.com/">Daddy Forever</a> : : <a href="http://www.embeddedstar.com/">Embedded Star</a> : : <a href="http://edageek.com/">EDA Geek</a> : : <a href="http://edablog.com/">EDA Blog</a><br />© %%date[Y]%% Online Destiny Ltd : : <a href="%%blogurl%%">%%blogname%%</a> is a trademark of Online Destiny</p>
Go to the Better Feed WordPress plugin page for more info.
[Update: The extra stuff you insert into the feed will not be displayed unless you are using full feed. However, you can limit how much of your post is displayed in the feed via the <!–more–> quicktag.]
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