From What I know (from a teacher who I sent to your site):
E-mail may be super effective, but you may have more luck selling to teachers if their students don't need an e-mail address; if they can put in their (pseudo)name or 'school number' and a passcode or some such to upload to an online interface. (w/o an e-mail... w/o storing personally identifiable information of students online, etc)
We'd love it if teachers didn't have to input any information at all! Unfortunately, email addresses are the only universally accessible means of communicating with students when we aren't integrated with their school systems. It also fits better with the typical student's workflow.
E-mail may be super effective, but you may have more luck selling to teachers if their students don't need an e-mail address; if they can put in their (pseudo)name or 'school number' and a passcode or some such to upload to an online interface. (w/o an e-mail... w/o storing personally identifiable information of students online, etc)