add_filter( "adverts_tpl_single_posted_by", function($content, $post_id) {
    $post = get_post($post_id);
    if($post){
        $profile_url = '#';
        if(class_exists('PeepSoUser')){
            $PeepSoUser = PeepSoUser::get_instance($post->post_author);
            $profile_url = $PeepSoUser->get_profileurl();
        }
        $content = sprintf( __("by <a href='{$profile_url}'><strong>%s</strong></a>", "wpadverts"), esc_html( get_post_meta($post_id, 'adverts_person', true) ) );
    } else {
        $content =  "<span style='color:red'> Guest <strong>%s</strong></span>";
    }

    return $content;

}, 99, 2);