Load balancing is a method of sharing the amount of work that normally a single computer has to perform, to multiple computers. Using load balancing heavy tasks can be divided and processed among multiple computers, this way we obtain a better performance, less response time and maximum resource usage. This technique is used mostly used in computer clustering, where multiple computers are connected to each other, in order to divide the tasks of the system.
Since the tasks are distributed among multiple machines, redundancy is archived, which leads to greater reliability.
Web site which recives a high amount of traffic each day uses load balancing, this way their website will still repond very fast, no matter how much traffic it recieves.