As a security precaution against the sending of any errant messages or any malicious messages stemming from a compromised account, we have changed the maximum recipient limit per email to 250 for staff and 100 for students.
Shared Mailboxes are used when multiple people need access to the same mailbox, such as a college project, campus team, or other function that might be shared by multiple people.
There are rare circumstances where you might need to manually update your computers Outlook windows desktop Address Book, where you need to send mail to an account or mailing list that was just added and you cannot wait for the automatic daily update.