bbPress.org

You don’t have to change the bbp_rel_nofollow filter, just add another filter like this in your functions.php:

<?php
add_filter( ‘bbp_get_reply_content’,’links_blank_follow’, 90 );
add_filter( ‘bbp_get_topic_content’,’links_blank_follow’, 90 );

function links_blank_follow() {
// add nofollow or target blank to links
}
?>

As for the function itself, I wouldn’t know how to do that, but you should be able to put it together, could start here.

Let me know!