What is an activity?

An activity is a discrete step in a business process (workflow). Activities range from calling a remote service to perform a task, e.g. calculating taxes, performing currency conversions, looking up inventory, to custom-defined services. Activities are orchestrated together together a workflow in BizTalk using XOML (eXtensible Object Markup Language). In other BPM (Business Process Management) solutions, activities are orchestrated using BPEL (Business Process Execution Language). Both XOML and BPEL are XML-based markup languages used for orchestrating workflows. BPEL is an industry standard; XOML is Microsoft's propriety solution.

How Microsoft BizTalk workflows take advantage of cloud-based activities

While the first definitions of cloudbursting are focused on reactive capacity management, Microsoft appears to be taking a proactive approach to cloudbursting and capacity management. By encouraging developers to utilize the compute capacity of BizTalk labs up front during the design and development process, it alleviates the need to react hastily later when it becomes apparent that more compute resources are necessary for a specific workflow activity.

The concept remains the same: utilize the cloud for additional capacity when it is apparent your own data center can't handle the load and it is cost-prohibitive to invest in additional servers and infrastructure to increase capacity.

One can easily imagine that future offerings might include the ability of other organizations to subscribe to and use activities developed by third-parties, essentially offering yet another path to monetize the cloud.