Amazon Webservices (AWS) has announced two days ago a new feature for their Simple Storage Service, namely versioning. Every object (file), stored in a bucket with versioning enabled, may have an arbitrary numbers of versions stored. Every version may be either retrieved or irrevocably deleted at any moment.
S3 has already been used for versioning; namely, mounting it as a file system and storing the actual version control systems repositories "on the cloud". The high reliability of S3 made it possible to handle that task using such means as s3tools and/or Jungle Disk to synchronize with cloud storage or use it directly.
However, using version control system assumes a certain level of experience and knowledge of how the version control systems work. The new feature makes it possible to simply overwrite current versions of data stored on the cloud without a risk of losing earlier versions.
Thus, this long-expected feature contributes to greater data safety and, even though currently just few existing command-line utilities (such as aws) are able to control versioning feature, this feature can result in greater variety of end-user tools making use of cloud storage, to ensure data are safe and secure.
The obvious drawback is all the versions are still kept in the same bucket (thus raising the maintenance/storage price); also, there's no obvious way to restore a definite version of a number of files at once; however, it can be implemented with little overhead.
You can find more details on the new feature in the Amazon Simple Storage Service developer guide.
