"There is a lot of selective research and cherry-picking of
methodologies.
"GNU/Linux is very commonplace on servers. Virtualisation
requires those servers to communicate between and within one
another, either through open standards or 'interoperability', which
is typically a two-way bridge. Microsoft is fiddling with companies
like XenSource (now absorbed by Citrix) and VMware (now run by
former Softies) to interfere.
"In order to understand how GNU/Linux is doing against Windows
on the server, a market survey would be required which is global.
It is harder and more expensive to conduct a survey based on actual
deployments (global in particular), as opposed to assembling and
aggregating numbers of shipments from market leaders."