The purpose of a load balancer in web hosting is to distribute incoming network traffic across multiple servers to ensure optimal resource utilization and prevent any single server from becoming overwhelmed. By managing the traffic, load balancers enhance the performance and reliability of web applications, ensuring that users experience minimal downtime or latency. They also provide redundancy: if one server fails, the load balancer redirects traffic to the remaining operational servers. This scalability enables websites to handle fluctuating traffic levels efficiently, improving overall user engagement and satisfaction.