I really needed to see who invited this user and it's not easy if you have 100k invitations. So i tried to show the inviter of the member on his/her bp profile.
Well first i thought to create another shortcode function but then i realized that using the current myinviter short code would be a lot easier. Current shortcode show the inviter of currently logged in user. So the members may only see their own inviters.
Here it goes, just paste in your bp theme files (I use it at members/single/member-header.php)
<?php echo "Inviter: "; echo do_shortcode('[myinviter id="' . bp_displayed_user_id() . '"]'); ?>
Hope you like :)
Edit: It won't show anything if he/she was not invited by anyone.