I'm actually in the middle of designing a Workflow-as-a-service for my current employer (based on jBPM 5). However, this isn't Workflow-with-a-capital-W. It's

I'm actually in the middle of designing a Workflow-as-a-service for my current employer (based on jBPM 5). However, this isn't Workflow-with-a-capital-W. It's not even a state machine. SWF is actually a distributed-processing task queue with persistent state and execution history. Which is pretty cool.