The process of commoditisation is simply the movement between the novel, rare and new to the common, ubiquitous and necessary. As such the nature of a system changes in the process from for example potential high worth, scarce, risky, non standard and non-essential (source of CA) to low cost, ubiquitous, low risk, standardised and necessity (CODB).
Much of IT is CODB. That is why we are starting to see the first utility like environments for IT appear (whether at the HaaS, FaaS or SaaS level). However such environments whilst they often contain necessary services for any business at a lower cost than the build your own variety, generally they are neither low risk nor standardised.
Low risk in this context would mean multiple providers of the same service which you can swap between, as opposed to the implementation details of any one provider. To be able to swap between services you need not only standardised services but multiple providers and the freedom to move data, application or framework (depending upon which level of the stack you are talking about) between the providers.
In this context open source is a necessity to provide not only the base standards but also an operational means of implementing that standard. It is neither a tactic or a strategy.
However, open source (and in this context I mean ideally GPLv3 over other licenses) is not sufficient, you also need some form of additional information to ensure the users of such services that they aren't being locked-in, or that this provider is really compatible with another or they can run their own installation should they wish to.
This can only be achieved through monitoring and the use of trademarking, by an authoritative group providing assurance to end users that this provider meets the standard, that any primitives have not been modified and that what you run with one provider will work on another.
The idea of utility computing, running on others infrastructure etc are bundled with other concepts into the term web 2.0. However, the importance of the term is not the details but that it describes that there are some fundamental shifts from an old world to a new world.
There are changes occurring between users and companies, ownership of information, producers vs consumers, conversation vs product, virtual vs real business, the spread of the idea of openness into business, hardware and other areas, the commoditisation of sections of IT and in particularly the web 1.0 components of it.
It's all about the new stuff, creative destruction and new sources of CA and worth.
Is it a buzz word? Yes, but it's a timely intervention to enable us to start letting go of the things which matter but we shouldn't be concerned about.
It's all about progress, which is the only true sustainable source of worth.
--- Update April 2013
Depressingly, almost six years later, we are still talking about the issues of interoperability, trademarks and competition in the compute utility space.
The terms have changed, HaaS has become IaaS, FaaS has become PaaS and compute utility has become "cloud" but the concept remain the same. Progress has been slow in the open source world.