Email Services
Functional units
-  Transfer 
-  Delivery 
-  Mailing lists 
Basic operational principles:
-  Simple architecture based on open standard protocols (SMTP, IMAP, POP) 
-  Proper consistent naming and management 
-  Service monitoring (postmaster account) 
-  Personal data protection policy 
-  Security 
-  User education 
-  Spam and virus handling