With about 500 “students” enrolled, emailing individually is difficult because of limits to prevent spam. I started a DEEP VALUE group (in communities) at Google. Click on the link below (if you haven’t already joined–I sent out an invite to all my distribution list this morning). You may be required to have a Gmail account, but that is an easy process. Then you can keep your course work separate from your usual emails.
I will be communicating via emails with this DEEP VALUE group as well as posting here. If you decide not to join the group, you can still email questions/comments to me at firstname.lastname@example.org
https://groups.google.com/forum/#!overview then type: DEEP-VALUE and ask to join.