I am very interested in this issue
I have just posted something else about it
Can't you have javascript close the session on some browser.onClose event?
maybe rederecting the browser to logout.php3, canceling the close event...
Or if you updata a client's cookie every
15 seconds (can we do that!?) and then pick-up some usr_id, last_session_id, last_page_id, seconds_id adn update the database?
shouldn't we check the cookies we are (you are?) accepting everyday while browsing the net and see if they do that this way...specially the 'big ones'...
I just wonder... because i'm sure 'they' have allready managed this a 'long' time ago...
André