Sender (FROM)                TO                     CC                    BCC                                             Note                                    
 ---------------------- ---------------------- ---------------------- ---------------------- ------------------------------------------------------------------------- 
  personA@email.com      personB@email.com      -                      -                      Normal (no one on mail list get this mail)                               
  personA@email.com      mail@mailinglist.com   -                      -                      Normal (everyone on mail list get this email)                            
  mail@mailinglist.com   personA@email.com      -                      -                      Normal (personA@email.com is subscriber to mail list)                    
  personA@email.com      personB@email.com      mail@mailinglist.com   -                      Not normal (could be private communication, no permission from personB)  
  personA@email.com      personB@email.com      -                      mail@mailinglist.com   Not normal (could be private communication, no permission from personB)