As photographers keep accruing more and more terabytes of images, these services will become more and more affordable. There are many players in this space and I think we will see some photographer niched sites in the near future.
Amazon.com Amazon Web Services Store: Amazon S3 / Amazon Web Services: “Amazon Simple Storage Service (Amazon S3)
Amazon S3 is storage for the Internet. It is designed to make web-scale computing easier for developers.
Amazon S3 provides a simple web services interface that can be used to store and retrieve any amount of data, at any time, from anywhere on the web. It gives any developer access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of web sites. The service aims to maximize benefits of scale and to pass those benefits on to developers.”
Other players in this space. (via TechCrunch)