If you want to learn some more on the history of VM, there's already a VM History and Heritage Reference page over here.
This anniversary seems to have been a good reason for Bill Bitner to start a blog on this called : '40 Reflections for 40 Years of z/VM'. You can find it over here. The author's intentions ?
As the IBM z/VM product approaches its 40th Anniversary on August 2, 2012, the author takes time to reflect on the product and his experiences.Go and have a look at it. One of the questions that, obviously, pops up is "What is a VM?". In another post Bill refers to Brian Wade's phrase saying it is z/VM's role to "faithfully replicate the architecture". He also comments on the z/VM community, the people behind the product (IBM, customers), influential people etc.
I think I'll pass the link along to my VMWare colleagues as well. After all they might be interested in how VMWare will evolve the next 30 years.
As I always say, just check it out !