  Social goods are goods that grant value not only to their owners but also to
the owners' surroundings, be it their families, friends or office mates. The
benefit a non-owner derives from the good is affected by many factors,
including the type of the good, its availability, and the social status of the
non-owner. Depending on the magnitude of the benefit and on the price of the
good, a potential buyer might stay away from purchasing the good, hoping to
free ride on others' purchases. A revenue-maximizing seller who sells social
goods must take these considerations into account when setting prices for the
good. The literature on optimal pricing has advanced considerably over the last
decade, but little is known about optimal pricing schemes for selling social
goods. In this paper, we conduct a systematic study of revenue-maximizing
pricing schemes for social goods: we introduce a Bayesian model for this
scenario, and devise nearly-optimal pricing schemes for various types of
externalities, both for simultaneous sales and for sequential sales.
