Early next year the internet giant Yahoo! intends to open source its cloud infrastructure. This infrastructure is described as something between Amazon EC2 and Google App Engine. While Hadoop, Traffic Server and some other projects well known in the community were born at Yahoo! form the basis of a application level scalability the Yahoo! Cloud will provide the missing bits. Rather than offering raw virtual machines as Amazon EC2 does it provides pre-configured containers of server power. Amazon EC2 is identified as IAAS (infrastructure as a service) and Google App Engine more as PaaS (Platform as a Service) it is interesting to see where will Yahoo! Cloud finds its identity. It is also to point out that with this decision Yahoo! is really standing out because neither Google neither Amazon has open sourced their cloud implementation.Google has published a document about Map Reduce which subsequently was the basis for Hadoop. On the other hand there are open source cloud implementations like Eucalyptus project which recently gathered momentum but no one of them has been proven in the scale Yahoo! Data Centers has. From the developer blogs of Yahoo we can see that there are also other projects related to the cloud namely Sherpa and MObStore. Sherpa is scalable key value store similar to Amazon Dynamo and MObStore is analogous to Amazon S3 and Facebook's Haystack. So I am personally really curious to see Yahoo!'s Cloud implementation.