The coarse and fine grain trade off is really a matter of latency and usability. At the end of the day, you should move to a good SOA, with the right services exposed that do the right things, and not be as concern about granularity. Thus, web services that implement fine grained interfaces, and are meant for local invocation, will work well. Moreover, web services that implement fine grained interfaces and are meant for distributed invocation, and is on a low-latency network, will also work well.

Indeed, this is really an issue around service design, and we should really get off of this fine grained/coarse grained thing. It’s just causing unnecessary confusion. So, let’s talk service design, and in the process, how granular services should be.