Using your new format URL Existing customers can start using their new format URL right away. After you upload your web pages and start using a URL for the very first time. After you change your URL to use one of your other e-mail names, perhaps john.smith instead of smith.family. Few customers do this. This does not present a problem - simply use the equivalent old format URL in the short intervening period.
Most browsers display the URL of whatever page they are currently accessing.
It can manifest itself when, for example, hyperlinking from your guestbook thank you page back to your home page.