S3 offers volume storage via a Web-service interface, allowing users in the United States or Europe to store any amount of data and then download or delete it from anywhere.

'Over 29 Billion Objects'

Amazon said its service is presently storing "over 29 billion objects," which is an increase from 22 billion at the end of the second quarter. S3 has received, during its peak at the beginning of this month, more than 70,000 requests per second to store, download or remove one or more of those objects.

The new tiered pricing for U.S. customers starts at 15 cents per gigabyte for the first 50 terabytes of storage used each month, on a sliding scale that goes down to 12 cents per gigabyte for storage over 500 terabytes.

Alyssa Henry, S3 general manager, says the growth of S3 has allowed the operation to "become even more efficient and further lower our operating expenses," which has helped the company to pass along savings to customers. She noted that, in addition to this new storage savings, S3 recently lowered its data-transfer costs.

Amazon said S3 is being used by a wide range of companies. For example, National Geographic's topo.com offers topographic maps that users can buy for planning and sharing trip information. "Prior to Amazon S3," said Paul Glauthier, National Geographic Maps vice president, "the resources required to host such a large data set would have been cost-prohibitive."

Also cited was Oracle, whose Secure Backup Cloud module uses S3 for its scalable database backup.

'Boost to Cloud Computing'

Al Hilwa of industry research firm IDC said the current economy "will give a boost to cloud computing" as utilized by S3 and others because of the lack of up-front expenses and because customers need to pay only for what they use, not for excess capacity that might or might not be needed during peak times.

Oracle, for instance, noted the attractiveness of S3 to its customers because of the reliability, the unlimited capacity, and "no up-front capital expenditures."

Hilwa also noted that S3's main focus is providing storage of data for applications, which can draw upon huge databases, rather than simply dead storage of files.

He pointed out that, while Amazon may have realized savings from the scale of S3, the company wouldn't lower prices without a reason. The reason, he said, is either that it sees an opportunity for greater adoption, especially given the economy, or because of new competition -- or possibly both.