Shantanu's Blog

Route 53 allows us to have dynamic IP assigned to load balancers. For e.g.
I can have a domain name "uswest.shantanuoak.com" that will point to a mysql load-balancer hosted in the region uswest2 named myLB-1698217425.us-west-2.elb.amazonaws.com
I can also have a domain "useast.shantanuoak.com" that will point to another load balancer in some other region, for e.g. usEast

All the delivery boxes from that respective zones will talk to their own address (like uswest.shantanuoak.com) and not the load balancer address. The advantage is that if uswest mysql balancer has some issues, the traffic can easily be routed to useast mysql load balancer by making chagnes to route 53. Another advantage is that we can replace the load balancer without affecting the operations.
Here is an image from flickr.
http://www.flickr.com/photos/shantanuo/7492825534/in/photostream/

This can also be used for Creating Latency Resource Record Sets.

http://docs.amazonwebservices.com/Route53/latest/DeveloperGuide/CreatingLatencyRRSets.html

Route 53 latency-based routing lets you use DNS to route end-user requests to the EC2 region that will give your users the fastest response.