Thank you ALL for the explanation. Now I know something more but yet not sure whether the following procedure will work for different users.The procedure is like this: In my web application I would like to tell a user (when he is doing shopping to a shopping cart), that he is signed with his ID. To do so, in the login page ( where the user inserts his ID and password) I use request.session['UserIsLogged'] = UserID and on a page, where I would like to inform the user that is logged in,I will check the 'UserIsLogged' session to find out the signed user's ID. But will be the 'UserIsLogged' session different for different users? Thank you for your help. Regards, L.