Akamai and Sandpiper have better distribution than you will be able to achieve anyway. By working with a service such as these, you can achieve redundancy, scalability, and a better customer experience with minimal pain, anguish and gnashing of teeth. The cost of this kind of caching is also significantly less than the cost of maintaining your own servers in numerous networks. If you don't make extensive use of databases, distributed sites may make sense. However, if you make extensive use of databases, particularly inserts and updates, you probably do not want to use distributed sites.
Database replication can be a PITA as it is.
We actually tried to make this work for the Fool. We had distributed sites and hoped to use a database server at each site. After getting into the replication project, we decided it was not worth the effort. There was one huge problem we could not get around. Suppose a customer changes information in a database on a server in New York.