function kiedy($ts) {
   $ts=time()-$ts;
   if ($ts<60)                   
       // <1 minute
       return $ts." seconds ago";
     elseif ($ts<60*60)                     
       // <1 hour
       return floor($ts/60)." minutes ago";
   elseif ($ts<60*60*2)             
       // <2 hour
       return "1 hour ago";
     elseif ($ts<60*60*24)             
       // <24 hours = 1 day
       return floor($ts/60*60)." hours ago";
     elseif ($ts<60*60*24*2)           
       // <2 days
       return "1 day ago";
     elseif ($ts<60*60*24*7)           
       // <7 days = 1 week
         return floor($ts/60*60*24)." days ago";
   elseif ($ts<60*60*24*30.5)           
       // <30.5 days ~  1 month
       return floor($ts/60*60*24*7)." weeks ago";
     elseif ($ts<60*60*24*365)           
       // <365 days = 1 year
       return floor($ts/60*60*24*30.5)." months ago";
   else         
       // more than 1 year
       return floor($ts/60*60*24*365)." years ago";
};