Using a php like the necro counter is fine, set up a small swf with 3 pages, call the value of the counter on page 1, page 2 add 1 to this value then page 3 gotoAndPlay(2). This will keep the counter running. Now all you need to do is save the value of the counter at some interval or on some action. This could be a mouseover of this or another swf on the same page, or it could be a time interval.