This excerpt taken from the WBMD 8-K filed Nov 21, 2006.
Physician-Based Promotional Programs
The Company provides Medsite Rewards certificates to incent physicians to participate in certain iDetail and Invites programs. These certificates may be redeemed for medically relevant products and are provided by MAC, a wholly-owned, non-consolidated subsidiary of the Company. Revenue is recognized when the certificate is redeemed and the product selected is shipped, or related certificate expires, based on the contractual value of the certificate. The Company also contracts with its clients to provide item-specific incentive programs for iDetails and Invites, where a physician is entitled to select medically relevant products from a catalog or brochure provided. Revenue is recognized when the product is shipped, based on the contractual value of the item selected.