Companies increasingly rely on “network” and “viral” marketing within their communication strategies. This study showed that providing viral products with specific features can increase their diffusion substantially. Products that were enabled to send automated notifications within a user’s local Facebook network upon adoption generated a 450 % higher adoption rate among Facebook friends compared with products without any viral features. Products that enabled adopters to send personal invitations to install the app generated an increase in the adoption rate by friends by 750 % more than in the control group. Although each personalized referral had a much stronger impact, notifications outperformed invitations in overall adoption. Automated notifications require no effort, and therefore substantially more messages were generated. The number of users who took the effort to send out personalized invitations was much smaller. A simulation of adoption beyond immediate individual networks showed that the passive-broadcast app experienced a 246 % increase in the rate of adoption, whereas adding active-personalized viral messaging capabilities generated only an additional 98 % increase, compared with the group without viral features.