If you change Internet Service Providers, you wont have to notify your friends of changes.
( simply update your e-mail forwarding settings and your mail will still get to you)

Makes you anonymous online, adding a layer of privacy and between you and the Internet.  Keeps your ISP email address  hidden.

Mail forwarding services automatically redirect all email sent to your new email forwarding address to an existing email address that you specify, in essence passing the messages on instantly to their destination. Because forwarding services don't store your email, you'll need to have an alternate email address to act as the receiver account.