What is Apache Kafka and when should you use it?

I'm learning distributed systems and backend development, and I often hear about Apache Kafka for handling real-time data streams. I understand it's a messaging platform, but I'm not sure how it works or when it's better than traditional message queues.

Can someone explain what Apache Kafka is, how it works, and its common use cases in event-driven architectures, log processing, and real-time analytics? A simple real-world example would also be helpful.