リファラのクエリーをうまいこと分解するやーつ。

parse_referrer_query.php

function perse_referrer_query(){
    if(isset($_SERVER['HTTP_REFERER'])){
        $referrer = parse_url(urldecode($_SERVER['HTTP_REFERER']));
        $tmp_queries = explode('&',$referrer['query']);
        $queries = array();
        foreach($tmp_queries as $query){
            $tmp = explode('=',$query);
            $queries[$tmp[0]] = $tmp[1];
        }
    }
}