Amazon S3 (Simple Storage Service) is an adjustable online storage service tailored towards companies or developers with larger or variable storage needs. Data can be stored or retrieved through a simple web interface from any computer at any time. S3 uses the same storage infrastructure that Amazon users for its primary e-commerce business.S3 was designed with a small number of features. Stored objects cannot be larger than 5GBs, but users can store an unlimited amount of objects. All objects are retrievable with a unique key code assigned to each user. It runs on REST and SOAP interfaces which can work with any internet development toolkit. Its default download protocol is HTTP, but for high-scale distribution a BitTorrent protocol can be used to lower costs.There is no minimum fee or activation charge. Storage costs $0.15 per GB-month.Companies large and small are using S3. They include Microsoft, Xerox, Linden Lab (Second Life), Powerset, Smugmug, Pownceand others.