With CloudFront, Amazon caches Web content in 14 locations in the United States, Europe, and Asia via its Simple Storage Service and network of data centers. Akamai, by comparison, has servers in 70 countries to monitor and optimize traffic routes. CloudFront is a simple service, whereas Akamai and Limelight have several tiers and product variations often aimed at much larger customers. So, for now, Amazon may be looking to offer content delivery services more for startups and Amazon Web Services customers.
When a user loads a Web page that has content stored in CloudFront, the browser will be directed to whatever is the nearest cached location to the user's IP address. That means visitors to Web sites that use CloudFront will see decreased latency if they are far away from the original site of the content, since CloudFront pulls the content from a cached version closest to the user.
Amazon anticipates CloudFront will be used for "frequently accessed Web site components": multimedia and download files. Several sites, including task management Web app Smartsheet, e-commerce site Woot, and social games site Playfish already use CloudFront to distribute content.
The interface is relatively simple. Customers sign up, upload content into Amazon S3, use a standard Web services call to create a CloudFront distribution, generate URLs for content, and point their Web sites in that direction.
One downside is that CloudFront users have to store their data in Amazon's S3 storage service. It's a positive for companies and developers already using S3 who have been demanding a content delivery network, but not an option for the many companies and developers who don't want to use S3. CloudFront's pricing also is separate and in some ways additive to S3 pricing, in that S3 accounts get charged for requests and bandwidth usage when CloudFront first caches the S3 data.
Just like other Amazon Web Services (and unlike some other content delivery services that have up-front costs), CloudFront is entirely pay as you go. Cost varies by location, with prices cheaper in the United States than elsewhere. Pricing is also more expensive if less data is transferred. In the United States, CloudFront is priced at 17 cents per gigabyte up to 10 TB, but 9 cents per gigabyte after the first 150 TB of bandwidth has been used. The most expensive location to cache data is Japan, which starts at 22 cents per gigabyte for up to 10 TB of data transfer. Amazon's prices also don't include other taxes or fees.
Amazon's prices won't compete at the highest volumes, where independent analyst Daniel Rayburn estimates some companies are charging 2.5 cents per gigabyte if they transmit more than 1 PB of information.
Among CloudFront's other limitations are that, at least according to cloud management company RightScale, CloudFront's usage reporting isn't as detailed as that of other content delivery networks, and its offering is one-dimensional. Akamai, for one, has several content delivery services and tiers. CloudFront also only supports HTTP, not more secure HTTPS.