I personally see both the "message" and the "protocol" as part of Service-Oriented Architectures but Jeff Schneider sees a difference. Hmmm... Can't make up my mind now but this post is worth a read. Also, if you haven't seen it, here's Jeff's paper on the "World Wide Grid". Jeff's use of the term "Grid" is consistent with the way we've been using it in our work. I agree that the "Grid" is not only about bringing super-computers together or another flavour of SETI@Home; instead, the Grid is about interconnecting organisations, creating distributed applications that span the globe, enabling interconnected devices that utilise those applications, etc.