A deleted mailbox may be recovered if it has not been permanently purged. By default, deleted mailboxes are not permanently purged for 30 days.
Recipient objects can have multiple email addresses. The primary email address is the one that appears in the From box of all messages the user creates for the corresponding connector or protocol.
The alias, the part of the email address before the "@" symbol, does not have to match the user logon name.
Hiding a mailbox simply prevents it from showing up in the Exchange address lists. Groups can also be hidden from the Exchange address lists, preventing users from finding the group to send it email.
By configuring the Send on Behalf permission, messages have the following format in the From box: DelegatedUser on behalf of MailboxOwner.
By configuring the Send As permission, messages appear to have come from the mailbox owner, even though another delegated user has actually sent the email message.
Universal distribution groups or query-based universal distribution groups allow you to quickly send email messages to a large number of Exchange users.
Expansion of mail sent to mail-enabled groups occurs by default on the first Exchange server that handles the message.
