... Any Application.
This talk on the future of virtualisation by James Hamilton is worth watching.
Open standards is a big topic today - it's even a blue beanie day.
It affects all layers of the XaaS stack, and there are groups such as Data Portability which have formed to champion the need for such standards in particular areas. You also have the DMTF who announced an Open Standard for System Virtualization Management.
James Urquhart has an excellent blog post covering the issue of application and data portability. I happen to personally agree with James that unless there are open standards, then in most cases the sensible approach is to use utility like services behind the firewall.
"the adoption of standards-based technologies is a sound business strategy that helps companies minimize time to market, reduce costs, generate differentiated offerings, and drive a business model for sustained growth"
The most important thing about open source and open standards is that they level the playing field. I happen to agree with Kogut and Metiu that open mechanisms of development recognise "that distribution of natural intelligence does not correspond to the monopolization of innovation by the richest firms".
You never know where that next big idea is coming from ... it could be some surfer dude.