Try something like this in your template tags (or wherever in your theme):
function should_display_link() {
$post = get_post();
// Something went wrong, bail. (You should always have a post, in theory)
if ( ! $post ) {
return false;
}
$current_user = get_current_user_id();
// Assuming only logged-in users can subscribe.
if ( ! $current_user ) {
return false;
}
return absint( $post->post_author ) !== absint( $current_user );
}
In your template, you can use it like this:
<?php if ( should_display_link() ) : ?>
<!-- Your link code here -->
<?php endif; ?>