Posted Sunday, August 14, 2011 at 9:37 AM
This is what the FAQs say about whitelisting
FYI: "Whitelist" is the general term for allowing an email to come through from a specific email address every time, regardless of the content contained within the email. Whitelist is also sometimes referred to as a "Safe List" or an "Approved Senders List." If you and your Classmates whitelist email@example.com, messages that may not ordinarily get through will now be received and read every time.
Please note the Class Creator system does not send spam mail of any kind to your Classmates. And when we email you directly, the Site Administrators, we will only send you messages we think are important to the business of running your class web site. Thus you and your Classmates can whitelist firstname.lastname@example.org with confidence that spam email will never be sent by us. Taking these measures will help ensure that all Classmates participating in your site can freely communicate without losing legitimate messages to spam filtering technology.