To compose an e-mail, use an @ sign in front of a user name. The system will autofill if you type in part of it. To include more than one person, leave a space after the first name and type another @ sign. If you mark it “public” everybody will be able to see and comment. “Private” is just between the addressees. E-mail is stored as plain text in the database, so don’t assume it can’t be read. Rest assured though, I don’t have the time.