A load balancer in a network serves the crucial purpose of distributing incoming network traffic across multiple servers or resources. This ensures that no single server becomes overwhelmed with requests, promoting optimal performance and reliability. By balancing the load, the load balancer enhances responsiveness and availability of applications or websites, minimizing downtime and improving user experience. It can also provide features like health checks to verify server status and initiate rerouting of traffic when issues arise. Load balancers are vital in managing web traffic, especially in high-volume environments.