Odds are that today most of the sites you visit have at least some of its content delivered through a content delivery network. In a nutshell, CDNs are used to cache data in various geographic locations around the world, so you can access that data faster by reducing access latency.
This is what the folks at Akamai have been doing for ages, but because of the diminishing costs of bandwidth and more accessible costs of running a datacenter, in recent years dozens of smaller companies have started to offer competing CDN services for all kinds of sites, small and large. TechSpot, for example, uses a CDN to speed up delivery of images and other forms of static content to you.
The search giant claims they are seeing speed improvements in the order of 25% to 60%, which sounds impressive. They will even let you sample your own site. Unfortunately for us however, our own obsession with speed means we’ve already taken all the obvious steps to optimize TechSpot’s page loads and after a brief test we discovered that Google’s Page Speed Service wouldn't speed up the site any further.
Google is offering Page Speed Service to a small group of users for free for a limited time. They eventually plan to charge a “competitive” rate for the service. Offering a CDN is just one of many Google initiatives to drive a faster Web in recent years, others include the Page Speed browser extension, the SPDY web protocol, Apache’s mod_pagespeed module, and the Chrome browser itself.