The forecast is cloudy and no, we’re not talking about the economy.  Instead, we’re shedding some light on yet another cloud computing service from Amazon Web Services, the web service infrastructure arm of Amazon which has offered cloud services since 2006.  Amazon is already noted for services such as Amazon Simple Storage Service, widely known as Amazon S3, and Amazon Elastic Compute Cloud (EC2).  Amazon S3 gives anyone access to cloud storage (you could store files in S3 using ElasticFox, a Firefox extension, for example) for cheap.  Amazon EC2 gives developers on-demand computing capacity through the power of virtualization at low rates depending on the amount of computing power needed.  Yesterday, however, Amazon released their long-awaited content delivery service known as Amazon CloudFront.

Amazon CloudFront is a cloud-based content delivery service that allows people to serve popular content (videos, images, documents, etc.) quickly.  In the past, S3 has been used much like a content delivery service which wasn’t exactly its purpose.  Many a blogger has served presentation slides in the form of a PDF or some other kind of downloadable from S3, but now they have the option of distributing those downloadables via CloudFront.

CloudFront works by integrating tightly with S3 in order to enable the swift delivery of files allover the world.  To get started, a file is dropped into an Amazon S3 bucket for storage.  Next, a distribution is created to associate the given S3 bucket with CloudFront.  A distribution simply associates the Amazon S3 bucket holding the content with a domain name which can be used to access the content stored in the bucket.  Finally, the domain name is used to access the content.

One of the most important reasons for considering using a content delivery service is speed.  Content delivery networks decrease the time it takes for content to reach its destination once it departs from its origin–a concept known as latency.  Low latency makes those cheesy YouTube videos we all adore that much better to watch since, depending on our connections, they begin playing immediately and continue playing without the annoying fits and starts and “Buffering…” messages we dealt with years ago (which is also a product of the proliferation of broadband).

To ensure low latency and thus quick downloads, content served from CloudFront is cached at 14 edge locations around the world–New York, DC, San Francisco, Hong Kong, and London to name a few.  When a person accesses the content to be delivered via CloudFront, the edge server in closest geographic proximity to that person serves up the content.  If that server does not have the content cached, it’s pulled from S3 and cached until it expires.  Content is cached at an edge location for 24 hours by default.  A longer expiration date can be set, however.  Upon expiration, the file is cleared from the cache and if it’s needed at that edge location again, it’s pulled from its original storage location in S3.

Why would somebody really care about CloudFront, though?  Say you’re a movie director (or you know a burgeoning Spike Lee), for example, and you’re going rogue and planning to release your next soon-to-be-critically acclaimed full-featured blockbuster on the web without the help of traditional distribution channels.  You could drop your movie into Amazon S3 and enable quick worldwide delivery of it via CloudFront.  Again, CloudFront would only be of interest if your movie was indeed in serious demand as CloudFront makes more sense for those offering frequently downloaded content.  Amazon recommends continuing to use S3 for content that needs to be stored and only occasionally accessed.

CloudFront is different from existing content delivery networks such as Akamai or CDNetworks, though, thanks to its tiered pricing model which falls right in line with its other Amazon web service offerings.  You don’t have to worry about minimum usage quotas and you pay for what you use in terms of bandwidth and storage–and that’s it.  CloudFront is important, then, because it allows anyone to leverage a fast content delivery network without the typical commitments or costs.  The implications of this, in a participatory web where everybody is creating something that they hope to get in front of as many eyeballs as possible, are enormous.  Much like S3 and EC2, CloudFront commoditizes an increasingly important service and makes it a reality for the little guy.