Link: Sam Ruby on Google Maps
Of course, the rest of the iceberg was that Google had simply tiled the Earth. In so doing, they converted a single web service (call me with a bunch of information, and I will provide you with a custom result) into a large number of individually addressable, cacheable, and scalable web resources.That's it. More the resources more is the opportunity to use Cache-Control headers, to use ETags, to distribute and load-balance the system.
In the same article, Sam also talks about how the web is not a service but a space. And in today's world adding more "space" will scale your system manifold than implementing a state-of-the-art service with the most optimal algorithm. Processor speeds have flattened. Today it's about dual-cores, quad-cores, (your-budget)-cores. The more cores your program can use to get the job done, the more scalable will your system be.
As Brian Goetz puts it: "Tasks must be amenable to parallelization". Parallelization comes for free with every resource you add. So add more resources and see your system scale.