EMC's been proudly showing data from the last two year's "IDC Server Virtualization Reports". Recently, an IDC person was present when I showed the pie chart, and he corrected me: "it's not market share" he said. I felt awful. I asked him how he would call it. He said he didn't know - but it wasn't a market share study.
So - let's see if I can be an engineer about something that isn't engineering, but is marketing. Read on...!