XenSource is really helping to make virtualization popular on the Linux platform. VMware and Microsoft (formerly Connectix) have really made virtualization popular on the Windows end with products such as VMware Workstation and Virtual PC.
It is a war and it will be interesting to see who the top contenders are. Currently, XenSource, Virtuozzo, and Virtual Iron are trying to become the top contender on the Linux and Windows platform. Clearly, VMware with their ESX server product is the 800 lb. gorilla but Xen would like to change that with the release of its open source hypervisor Xen 3.x. Including Xen in Red Hat and SUSE Linux distributions will allow this open source hypervisor to really compete with VMware.
Competitors such as Virtual Iron have already adopted Xens hypervisor in Version 3 of its release. I predict we will see much more of Xen in the future and I look forward to playing around with it!
Please take my poll on which virtualization vendor you prefer?