Google today launched a new content delivery network (CDN) called Page Speed Service. Like any other CDN, Page Speed Service provides improved Web performance by creating cached replicas of a site at locations distributed around the globe. Visits to the site are then served by a high-speed, low-latency local server, rather than having to use the authoritative master server.

Page Speed Service goes a little further than simply offering naive caching, however. It also performs a number of optimizations to the content it serves up. For example, it includes on-the-fly compaction of JavaScript, CSS, and HTML, stripping out the extra whitespace that can pad these files by 20-30 percent, and performs optimization of compressed PNG and JPEG images. Taken together, Google claims that Page Speed Service's features can make sites between 25 and 60 percent faster.

The service is also easy to get up and running, requiring little more than signing up and modifying DNS entries to refer to Google's servers. Not all sites will be eligible, however; configurations that use "bare" DNS names (no "www." in their Web addresses), SSL, or various other complex features can't use Page Speed Service. The company also has an Apache plugin to perform many of the same optimizations within the Web server itself.

Page Speed Service is not the first effort by Google to accelerate Web performance. The company has a proprietary alternative to secure HTTP, named SPDY, that it includes in its Chrome browser to reduce the overheads implicit in accessing secure content. A CDN is less radical approach to tackling the same problem, and much easier to adopt.

Page Speed Service is presently free of charge, allowing Web publishers to test and assess it. Google intends to charge for the service, but has not yet released details of the pricing, other than to say that it will be "competitive."