In the wake of the new federal CAN-SPAM Act, an EmailLabs audit of more than 100 opted-in emails (non client) discovered that a majority of permission marketers are exceeding most requirements of the Act, but remain confused over administrative aspects of the law.

In a new benchmark audit of major email marketers, EmailLabs found that 95 percent include an unsubscribe process, as mandated by the law. At the same time, just 56 percent were in compliance with one of the simplest aspects of CAN-SPAM - the new requirement to add a postal mailing address.
http://www.emaillabs.com/article_CANSPAMAudit.html