What is one of the main principles of effective viral marketing?

Offering products or services free of charge is a core principle of effective viral marketing because it incentivizes sharing and encourages widespread dissemination. When a product or service is provided for free, it lowers the barrier for initial engagement, allowing users to experience the value without any financial commitment. This can lead to higher levels of word-of-mouth promotion, as satisfied users are likely to share their experiences with friends and family, contributing to the viral nature of the marketing campaign.

Additionally, free offerings can create a sense of urgency or exclusivity, motivating individuals to act quickly to take advantage of the offer and share it with others. This principle taps into the psychology of social sharing, making it easier for a marketing message to reach a broader audience through organic channels.