ÉTS is now using a Single Sign-On (SSO) service. As time goes by, more and more applications should be connected to it.
When you access an SSO-enabled application, you will be first redirected to the Single Sign-On page (the one you are currently looking at). After entering your credentials, you will not have to enter them again as long as you are not disconnected, even if you access other applications.
If you log out of an application, you will have to enter your credentials again on the next access to any SSO-enabled application. However, you will not be disconnected from the applications to which you already logged on.