Question

I am looking for an WordPress plugin which allows only the subscribers in feed burner to download an particular file. Could any one help me with it?

Answer 1

Based on the answer of Virgin, what you basically have to do first, is make a Feed templates, which are located in the /wp-includes/feed-myposttype.php
Where myposttype is your custom post type name.

In order to change the default rss feed, you will modify the feed-myposttype.php template you made, and redefine the action ‘do_feed_rss2’, like this:

remove_all_actions( 'do_feed_rss2' );
add_action( 'do_feed_rss2', 'acme_product_feed_rss2', 10, 1 );

function acme_product_feed_rss2( $for_comments ) {
    $custom_type = 'myposttype'; //**your custom post type**
    $rss_template = get_template_directory() . '/feeds/feed-myposttype.php';
    if( get_query_var( 'post_type' ) == $custom_type and file_exists( $rss_template ) )
        load_template( $rss_template );
    else
        do_feed_rss2( $for_comments ); // Call default function
}

Another approach,is using this logic to evaluate if a post in the feed is part of a “special category”, and enable the download feature you mention only for that category.