Kirkpatrick, Katherine. USC Web mail deletes e-mails 180 days old. Daily Trojan Online. Sept. 3, 2004.

According to this article the USC just recently implemented a 180-day e-mail retention policy. All e-mail across the USC e-mail environment will automatically be deleted after 180 days. The article suggests this was driven by the Office of the General Counsel of the University and is related to search costs, security and privacy issues.