This view is very much exposed in the Eucalyptus utility Computing Architecture Initiative by the University of California, Santa Barbara (http://eucalyptus.cs.ucsb.edu/ ) one of its goals is to offer a "network as a service" boundary (multi-network was also mentioned). What this means is that instead of consuming as a service the infrastructure utility (Storage, compute) the network itself is also provisioned such that the access of the service is at the MAC address network point and the API of the provider. In simple terms this means the End User Device plugs into the network IP and accesses the service as a Network oriented service with all the aspects of the resources and provisioning behind this. This is quite a different story to selecting and accessing storage or compute power on demand. An analogy is like buying electricity units of power and storing this in a battery for use as opposed to taking your end user device and plugging it in and just drawing down the electricity as you need it during the use of that device. It's a matter of abstraction and ease of use and a key one in how on-demand services are access.
The development of online sustainable services needs to fully realize the aspect of what it means to live in the cloud service environment. With the fast evolution of Grid technology capacity and off-premise utility services the economics of on-demand service this is rapidly becoming a key decision point.
The element of network is essential to this paradigm as the speed of the data connection and volume of package and file download is a key limiting factor to the use of performance, scalability and extensibility.
As we become increasingly leveraged as an Information Economy, the role of network convergence with storage and capacity is increasingly the presence of how the channels of service and resources may be accessed. But this is probably only part of the story as other boundary points of service also exist in the content and the application and exchange collaboration capabilities that are provisioned within these channels.
The boundary management is very much the visceral Customer experience that is resolved in this on-demand service exchange. This spans today the EUC end with the form factor device on the edge service into the network up to the selection of the applications and hardware services consumed and then the experience of the service in execution in the business operation and its value add for business performance. The choice of service and the provision of service also renders other boundaries that need consideration: the Platform boundary it self on which the API to the Utility resource is connected and the address of the Operating System Image and the ecosystem template standards that an instance may run in. (The Eucalyptus example is that the Open Source Architecture works with the Amazon EC2 API and accesses it as a Storage Utility Service.) What appears to be the emerging case is that extensibility of service is more than the mash-up cloud service (Integration as a service) which does provide a co-existence path for old world (pre-cloud) and new world services but also the importance of "how on-demand service is consumed" as a collective noun experience. The development of Collaboration as a service and Communications as a service is clearly a boundary that extends the cloud radius and span of use beyond the definitions of utility services of five years ago as we see new service exchanges evolving into true online marketplaces.