"he hackers said the email boxes belong to Steve Mosko, president of Sony Pictures Television, and Amy Pascal, co-chairman of Sony Pictures Entertainment.
The Microsoft Outlook mailbox files run to several gigabytes and apparently contain thousands of messages sent to and by both executives over several months.
A handful of the emails, seen by IDG News Service, appear to include discussions between company executives, lists of phone messages that include contact details for executives at other companies, business information, and personal messages to family members http://www.computerworld.com/article/2857272/legal/hackers-contacted-top-sony-executives-before-attack.html
There is nothing as critical as a mailbox from an engineer or businessmanagement
but they hardly get an double authentification, password or encryptionprotection or to say automatic archiving to another protected environment if it is put in for example a folder secure archive
this is what I personally think : if one puts a mail in a folder 'secure archive' the exchange server takes them once a day and puts them in an archived but secured mailbox that the owner can only access online and only if he uses specific procedures (eventually password, specific hardware or decryption key and so on....)
so no more old mails that are lost during a hack or leak
and for the mails of today - one should use the same protection as for important files. Sometimes files are secret on the server and hard to reach but are send around in mailboxes as if it is candy