Amazon S3 Introduces Reduced Redundancy Storage (2x vs 3x)
http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?DataDurability.html#UsingRRSUpdate: Werner Vogels weighs in: http://www.allthingsdistributed.com/2010/05/amazon_s3_reduced_redundancy_storage.html