After having hosted a Cloud Computing event in November and hearing how companies are dipping their feet in the cloud, the next logical step we discussed was inter cloud communication. As a small company I may buy into Salesforce.com for CRM, Workday for HR/Financials and Google AppEngine for custom apps. How do I tie these solutions together for data synchronization? What if the data to be exchanged is extremely large? What solutions can I use to do the heavy lifting?
Service Bus solutions either deployed locally or in the cloud provide a composition medium to support such interactions. Cloud platforms expose public APIs via REST or SOAP for near-real time communication.
Large data sets and exchange of this for processing is being investigated by a interesting consortium called Open Cloud Consortium.
Another interesting area may be the creation of middleware in the cloud. Grand Central tried to support this in the early 2000 timeframe. It was a little ahead of its time but now we are seeing Amazon SQS, Microsoft Azure w/Biztalk and other similar platforms.