Single Sign-On is beneficial for anyone using multiple Seznam.cz services.
When switching between services, you don’t need to repeatedly enter your login credentials. If you want to switch from your email inbox to another Seznam service that is not automatically signed in, simply click on the Sign in option on the other service and confirm your login with a single click on the selected account.
At the same time, this feature does not restrict you in any way. If you prefer to continue using Seznam services under a different username, you can do so by clicking the Continue with another account button.

Tip: You can log out from any Seznam.cz service using the Log out button available on each signed-in service page.