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The Feed Ads Plugin adds text, which can be a link, image tag, or any valid html to the end rss feed entries. This is done randomly so that not every entry will have the text. In this way WordPress admins can extend the usefulness of the feeds with advertising or links to other sites.

Please be careful to enter valid HTML. The plugin does not validate the HTML that you enter, so it is quite easy to break your RSS feed.

The plugin allows for different messages. The random factor can be adjusted so that 1 in 100 entries will have the text up to 100% of entries will show the text.