I found this post which talks about Microsoft dog-fooding Hyper-V for the hosting of the MSDN and TechNet portals. This is meant to give potential customers confidence in the new virtualization platform from Microsoft & that it is production ready.
As users adopt server virtualization in their data centers, they will realize even more benefits from a virtual lab (a lab with virtual machines that they use in software engineering and pre-production). They can more easily create a virtual lab that mirrors their production environment (don’t get me wrong – even a data center with physical servers can be recreated in a lab using virtual machines – but it is easier when you have virtual machines in both your development/pre-prod environment and the production environment – you can directly re-use the exact same base virtual images/other artefacts across both environments for instance). Also, by using features from virtual lab automation products like VMLogix LabManager, Surgient, VMware Lab Manager the test & test environment creation process becomes that much more easier.
Like most software test engineers and IT operations engineers would agree – the creation of this production -like environment is very important for credible testing & to be sure that you’re testing on the ‘real environment’.