(ab)Used by Zynga earlier to great success with Farmville and Mafia Wars. https://knowledge.wharton.upenn.edu/article/is-zyngas-dependence-on-facebook-the-key-

(ab)Used by Zynga earlier to great success with Farmville and Mafia Wars. https://knowledge.wharton.upenn.edu/article/is-zyngas-dependence-on-facebook-the-key-to-its-success-or-its-downfall/ https://knowledge.wharton.upenn.edu/article/is-zyngas-depend...