Great announcement. The only problem with it is that it is not available today. But today will come soon enough...
For SalesForce, this is a huge step in saying they want to be a major Cloud deployment platform. They want all Java apps to run on their infrastructure - it is no longer about just hosting their own programming model. This also jumps up a level from what Amazon and Google and Rackspace are offering in terms of ease of use and deployment for Java apps. And of course their trump card is access to their database and apps and users - the thing that has proved a virtuous cycle of bringing 3rd party apps and more customers to SalesForce.
For VMWare and Spring, it is a major proof point of their platform and applicability for the Cloud. It gives them a solid use-case to focus their development efforts on to adapt Spring to the new era of Cloud-enabling middleware (not a trivial task), and provides a clear higher level use case for moving to the Cloud. Of course VMWare and Spring will be trying to become the plumbing for all service providers as they roll out Cloud offerings - so do not expect them to be locked into just this deployment over time.
From an eXo perspective, this is confirmation of the path that we are on - providing a set of Java-based services around Content, Collaboration, and Social that are Cloud-enabled. Just as you see the demo of a Java app working with Chatter in the Force.com demos to generate an activity stream, all of the other service providers and enterprises with their own Cloud offerings will need a similar implementation of services. While VMWare will offer Zimbra for mail and some collaboration applications, eXo will be a useful addition.
While it has been cool to see Amazon and Google lead the industry into Cloud computing, this move promises the next few years will be very exciting indeed.