Procedure. Each participant read a short scenario that contained a description of the participant's relationship with a fictitious cellular telecommunication provider, "TelStar." It described the business relationship in positive terms, because satisfaction is usually a prerequisite for a recommendation (Biyalogorsky, Gerstner, and Libai 2001; Chew 2006). In the scenario, the employees in the shop and on the hotline were friendly, the coverage was fine, and the value of the offer was good. To manipulate reward size, we showed participants different TelStar web pages. In the small reward group, the web page indicated that TelStar was inviting its customers to recommend TelStar if they were satisfied with its services and offered €5 if they successfully recommended the provider (see the Appendix, Condition la). Participants in the large reward group read that TelStar offered €50 if they recommended the provider (Appendix, Condition lb). These reward sizes reflected the actual range of rewards offered for successful referrals that led to two-year contracts in the German cellular telecommunications industry. Finally, we pretested several reward sizes, and the chosen amounts emerged as realistic and indicative of small and large rewards relative to the value of the recommendation to the provider (i.e., a new two-year contract).