Interoperability (the ability to exchange and use information) between cloud computing products and services is required for unfettered competition between vendors and unrestricted choice for users.
Users must be able to come (no barriers to entry) and go (no barriers to exit) regardless of who they are (no discrimination) and what systems they use (technological neutrality).
Supporting vendors must therefore cooperate on standards, implementing those that exist (where applicable) and collaborating via an open process to develop those that don't, with a view to competing fairly on quality.
Open Cloud must meet the following requirements:
Open Formats: All user data and metadata must be represented in Open Standard formats.
Open Interfaces: All functionality must be exposed by way of Open Standard interfaces.
Open Standards must meet the following requirements:
Copyrights: The standard must be documented in all its details, published and both accessible and [re]usable free of charge.
Patents: Any patents possibly present on [parts of] the standard must be irrevocably made available on a royalty-free basis.
Trademarks: Any trademarks possibly present on identifier(s) must be used for non-discriminatory enforcement of compliance only.
Implementations: There must be multiple full, faithful, independent and interoperable implementations (for both client and server where applicable) and at least one such implementation must be licensed in its entirety under an Open Source Initiative (OSI) approved license or placed into the public domain.