What is a successful micropayment solution in the crypto sphere?
In the rapidly evolving world of cryptocurrency, a successful micropayment solution is paramount. Could you elaborate on what constitutes such a solution? I'm particularly interested in how it addresses the challenges of small transaction sizes, fees, and scalability. Is it based on a specific blockchain protocol? How does it ensure security and privacy for both merchants and consumers? Additionally, I'd like to know if it has achieved widespread adoption and what are the key factors contributing to its success. Your insights would be invaluable in understanding the landscape of micropayments in the crypto sphere.