How does a swarm work?

As a keen observer of cryptocurrency and financial trends, I'm particularly intrigued by the concept of "swarm". Could you elaborate on how a swarm actually works? I understand it's a decentralized network of autonomous agents, but what's the driving force behind its coordination? How do these agents come together to achieve a common goal? Are there any specific protocols or algorithms that govern the swarm's behavior? Also, what kind of tasks or applications is a swarm typically suited for? And finally, what are some of the challenges or limitations in implementing a swarm in the real world?