A long-lived match made in the cloud will require 
more detail than providers and brokers are currently offering
Buried in blogs around the Internets are references to a research survey conducted by research firm ESG earlier this year on behalf of VMware. While obtaining the full contents require more than my meager pockets contain, the summary data held several nuggets of gold, among them this one on compatibility across cloud and on-premise infrastructure:
Importance of compatibility: 78% of respondents reported that it was also important that their cloud service providers’ infrastructure technologies were compatible with their internal private cloud/virtualized datacenter. 
— New Study Shows Growth of Infrastructure-as-a-Service (IaaS) Adoption
I'm guessing that if they'd used a term more common to networking / infrastructure domains, say interoperability, they may have gotten more ping on this statistic. And yet, I don't think interoperability is exactly what this statistic refers to. Interoperability and compatibility imply some subtle differences. Compatibility implies a level of mutual understanding at the data level which, for infrastructure, means control-plane compatibility. Policy sharing, as an example. Interoperability implies a lower-level of exchange at the data plane, protocol processing and such.
Assuming that what these 614 global respondents – all IT managers with budget responsibility – were considering important is really mobility of infrastructure service application, i.e. operational consistency, across infrastructure, this leads to an interesting question. How does one know whether a cloud offers such compatibility or not?
Cloud Brokers: Catalogs
Most discussions on cloud brokers today continue to focus on establishing matches between consumers of cloud and providers via characteristics like price and location and sometimes performance. But rarely do we see a requirement for matching infrastructure service capabilities (and thus compatibility) across environments. Most cloud providers do offer catalogs of a sort from which services can be selected and provisioned, but these are not very shareable, if you will. They aren't in a neat, publicly accessible list that can be compared against other providers' lists.
Much in the same way registries were central to the notion of enabling the success of service-oriented architectures, cloud catalogs will be central to the success of cloud broker services' ability to compare and contrast offerings. Like profiles in on-line match making services, cloud catalogs will enable the process of matching consumers with providers based not only on simple characteristics like price and performance, but on deeper more critical capabilities like security and data integrity services, acceleration and optimization, and application-layer networking.
But it's not just about listing out services. To really get to the heart of compatibility, if what we're desiring is operational consistency, we need not only a more standard method of describing infrastructure policies (rule sets, processing directives, etc…) but the means to determine whether a given infrastructure service is capable of not only accepting but creating such a policy. Such policies must be abstract, they cannot be specific to any given environment. We need a way to describe the rules used to configure Amazon Security Groups, for example, such that they can be consumed and implemented by Rackspace, or BlueLock or an OpenStack-based private cloud framework.
While there are certainly efforts around describing aspects of cloud – virtual machines, applications, and even layer 2-3 networking – in a standards-based format, there's very little in the way of efforts to do so at the infrastructure service layers. Organizations for whom infrastructure compatibility is an important factor in the provider decision making process need exactly this kind of information to aid in their transition from private to hybrid and public architectures.
Cloud brokers could provide this level of metadata, if providers recognize the importance of disseminating that information in a way that's easily consumable and are willing to offer the data organizations need to make their decisions.
Making a compatible match between two people requires a lot more detail than just age, gender, and hobbies. It's also going to take a lot more detail than just price and location to make a compatible match between cloud consumers and providers when critical business functions are on the line.