There are a small number of organizations which offer IP whitelisting and/or licensed tags that can be placed in email (for a fee) to assure recipients' systems that the messages thus tagged are not spam. This system relies on legal enforcement of the tag. The intent is for email administrators to whitelist messages bearing the licensed tag.
A potential difficulty with such systems is that the licensing organization makes its money by licensing more senders to use the tag—not by strictly enforcing the rules upon licensees. A concern exists that senders whose messages are more likely to be considered spam who would accrue a greater benefit by using such a tag. The concern is that these factors form a perverse incentive for licensing organizations to be lenient with licensees who have offended. However, the value of a license would drop if it was not strictly enforced, and financial gains due to enforcement of a license itself can provide an additional incentive for strict enforcement. The Habeas mail classing system attempts to further address this issue by classing email according to origin, purpose, and permission. The purpose is to describe why the email is not likely spam, but permission based email.
