The authors introduce the novel concept of co-privacy or co-operative privacy to make privacy preservation attractive. A protocol is co-private if the best option for a player to preserve the user's privacy is to help another player in preserving his privacy. Co-privacy makes an individual's privacy preservation a goal that rationally interests other individuals: it is a matter of helping oneself by helping someone else. They formally define co-privacy in terms of nash equilibria. They then extend the concept to: general co-privacy, where a helping player's utility (i.e. interest) may include earning functionality and security in addition to privacy; mixed co-privacy, where mixed strategies and mixed nash equilibria are allowed with some restrictions; correlated co-privacy, in which nash equilibria are replaced by correlated equilibria.