The paper describes user behavior as a result of introducing monetization in the freemium educational online platform. Monetization resulted in alternative system growth mechanisms, causing viral increase in the number of users. Given different options, users choose the most advantageous and simple ones for them. System metrics in terms of the K-factor was utilized as an indicator of the system user base growth. The weekly K-factor almost doubled as a result of monetization introduction. Monetization and viral growth can be both competing and complementary mechanisms for the system growth.