Service-oriented computing has encountered an increasing importance for enterprises over the last years. With Web services, the major underlying technical basis is already in an advanced state. The service design area, on the other hand, still provides several research gaps such as the field of service identification and in particular the determination of an optimal granularity level for services. Granularity, assessed through coupling and cohesion considerations, is yet a rather unexplored domain when it comes to service-orientation, although several results from earlier design principles are available. In this paper we summarize the current state of the art in granularity measures and identify the implications emerging for practice and re-search. As we reveal, several existing measures for other paradigms, which might be adapted for service-orientation, are left unconsidered. Further research gaps, as the mainly missing empirical evaluation or a tighter inclusion in the development process, are also detected.