The upshot is that 25% of Dell's enterprise business is now running Linux.
Even as Linux grows, it loses market share to Windows servers, running either Apache or Microsoft's web server. The figures are somewhat skewed by Go Daddy's recent move to all Windows operation. Without that factored in, Windows is still taking share.
The reason? There are not enough Linux techs to go around. An organization can find technicians qualified and able to run Windows well and with reasonable security quite easily. Linux techs are harder to find. I, personally, have seen 4 or 5 organizations move away from Linux to Windows or Solaris because of the technician problem within the last 12 months. Neither the economic or quality advantages of Linux matter if an organization cannot find someone to run the systems for them.