Amazon is adding a new capability to help Web developers build applications to access data they store in its S3 cloud service.
The capability is called Cross-Origin Resource Sharing (CORS). According to Amazon, CORS defines a way for client Web applications that are loaded in one domain to interact with resources in a different domain.
Amazon says S3 lets customers store objects full of data in buckets, with each object holding up to 5 TB of data.  A Web services interface can retrieve any amount of data, and, because it’s on the Web, from anywhere.
A competing service is Google Storage for Developers.