Workaround for student email
Many schools don’t give student email accounts or permit students to use email at school. However, many Web 2.0 sites require unique email addresses, which poses a challenge.
A pretty usable workaround for this is this Gmail trick. If your teacher gmail account is firstname.lastname@example.org and a student uses the email address email@example.com, all email to that address will go to you at firstname.lastname@example.org. That allows you to register students for services that require a unique and valid email without maintaining or needing to monitor an email account for them.