Note that Oracle is nowhere to be found. It is possible that OVM is buried in Citrix's paltry 8%. (OVM is a Xen variant after all.) Having said that, it is the case that at least from a virtualization standpoint, Oracle has yet to gain any significant momentum, and VMware remains the incumbent majority marketshare leader.
Oracle has been behind the curve on virtualizing. Their stance on puting on their virtualizing brakes is most likely a ploy allowing them to get their act together. I will assume we'll see their piece of the pie increase by year's end.
What surprised me is Microsoft's Hyper-V momentum.