The customers that Amazon has chosen to test Cloudfront give some clue to the target audience. Woot, an e-commerce site that offers a different deal every day, is using the service to cope with spikes in traffic that occur right when a new deal is posted. "We're not [photo-sharing site] Flickr," says Woot's retail IT director Luke Duff. "We're just doing our sale images for products. As far as performance, we only really care about the current day's items." Since Woot already used other features of Amazon Web Services, he says, it just made sense to try Cloudfront, especially since the cost was "quite a bit less" than other services that the company investigated. And because of the site's volatile traffic patterns, pay-as-you-go works well for Woot, Duff adds.

Amazon isn't the only company hoping to fill this niche in content-delivery networks with a pay-as-you-go business model. Voxel, based in New York, has offered, for about a year, pay-as-you-go content delivery, including support for streaming video. Voxel CEO Raj Dutt says that he expects pay-as-you-go content delivery to appeal particularly to customers with unpredictable traffic patterns.

James Staten, a principal analyst at Forrester Research, believes that Cloudfront is likely to attract startups that are new to using content-delivery networks. But this might not be a bad thing for more-established players. "If I was Akamai, I wouldn't be too worried," Staten says. "Because [Cloudfront] is a limited implementation, it becomes a nice on-ramp for customers, when they mature, to move up to Akamai." Growing companies may eventually move on, he says, because "the value of a content-delivery network is directly related to how many locations it provides you." More-established content-delivery companies are currently much better than Amazon at providing sophisticated access to a wide variety of locations, Staten says.

But even though Amazon Cloudfront may be less sophisticated, Staten says that Amazon's popular S3 and EC2 products are "absolutely" going to draw companies into trying Cloudfront and any other add-ons that Amazon develops in the future. "If you're drinking the Kool-Aid and the experience is good," Staten says, "there's no point in not trying the additional services that they make available to you."