I don’t think anyone would argue that Amazon S3 is the big bear of the Cloud market, both on the virtual cloud infrastructure and the cloud storage side of things. Amazon S3 has more than 102 billion objects stored on it as of March 2010.
As befits a dominant player the interface that Amazon exposes for Amazon S3 is becoming so widely used that it almost becoming a standard with regards to how to connect into Cloud Storage. Many new or existing players in this space already support the interface as an entry point into their Storage infrastructure. For example Google Storage supports the S3 interface, as does the private cloud vendor Eucalyptus with its Walrus offering. Also the on-premise cloud appliance vendor Mezeo recently announced support for accessing their cloud using Amazon S3, as did TierraCloud. There are other Open Source implementations as well such as ParkPlace which is an Amazon S3 clone and bittorrent service that is written in ruby.
Additional to this, the multi-cloud vendor, Storage Made Easy has implemented an S3 entry point into it’s gateway so that you can use it with normal clouds even where they do not natively support Amazon S3, such as RackSpace, Google Docs, DropBox etc.
So as far as S3 goes it seems you can pretty much access a multitude of storage back-end’s using this API, which is not surprising as vendors want to make it easy for you to move from S3 to their proposition or they want their proposition to work with existing toolsets and program code. So is it good for cloud in general ? I guess the answer to that is both ‘yes’ and ‘no’.
‘Yes’ from the point of view that standardisation can be a good thing for customers as it gives stability and promotes interoperability. ‘No’ from the point of view that standardisation can easily stifle innovation. I’m happy to say that this is not what is occurring in the cloud storage space as the work around OpenStack and Swift demonstrates.
I think right now, S3 is as close as you will get to a de facto standard for cloud storage API interactions. It probably suits Amazon that this is the case, and it certainly suits consumers / developers. Time will tell how quickly this situations lasts.