Scalable internet services

With the growing number of internet users in today's world the internet service is on expansion. Scalability issues are on the rise as there is a huge gap between average and peak workloads. Average statistical loads across disparate communities is one way to solve the problem. Content distribution network (CDN) and other large distributed services can gain economies of scale by serving multiple customers. Services with high amount of personalized content require a large number of servers called Web server farm, use special techniques to make these servers work terms of performance and accuracy. Caching and replication are two methods for improving performance and the increasingly blurry division between them.