Can your system work with mine? A case of interoperabilty and open standards

SaaS-applications (apps) are developed and distributed rapidly on the internet (the cloud) these days and companies want to integrate these SaaS-applications. Just look at this Salesforce-site.
A SaaS-application can be tested for different reasons: functionality, performance, security etc.
For integration of SaaS-apps a test should be done.
Yeah nice Cordny, interoperability tests, what's new??
Well, this post is not only about interoperability, but also about open standards which are at the moment a big item in the cloud (SaaS is a part of this)-community and the digital (politics)agenda.
Both interoperability and open standards have a similar goal (provide exchange between systems). With respect to software, interoperability is used to describe the capability of different programs to exchange data via a common set of exchange formats, to read and write the same file formats, and to use the same protocols.
For Open Standards, according to Microsoft, an open standard is publicly available, and developed, approved and maintained via a collaborative and consensus driven process. But it applies both parties should be part of this process. At my PC Microsoft itself still can't open a ODF-document.
But there are protocols which are also open standards. One of them is SAML2.0, which you know, if you already have read my blog,is an open standard for authentication and authorization exchange.
And yes, Microsoft can deal with this protocol, see here.

However, both SAML2.0 and Microsoft (with AFDS 2.0) are evolving, so interoperability tests still have to be done. Especially because SAML2.0 is very flexible. Can Microsoft keep up?