Different websites will parallelize different parts of assembling a page. Amazon might partition the front-end web server into a recommender system, feed aggregator, and advertising service, which would in turn talk to their own databases. This would minimize the latency of the responses. So the server is working harder but reducing latency by some factor, which is extremely important to the customer. Studies show that people will walk away from a website if it's slow.
For easier access - http://perspectives.mvdirona.com/2009/10/the-cost-of-latency/
Different websites will parallelize different parts of assembling a page. Amazon might partition the front-end web server into a recommender system, feed aggregator, and advertising service, which would in turn talk to their own databases. This would minimize the latency of the responses. So the server is working harder but reducing latency by some factor, which is extremely important to the customer. Studies show that people will walk away from a website if it's slow.