These numbers almost assuredly are based on "units shipped" which means you only count a Linux sale if someone orders a server from Dell or HP and requests a RH

These numbers almost assuredly are based on "units shipped" which means you only count a Linux sale if someone orders a server from Dell or HP and requests a RH or Suse Linux license with it, rather than a Windows Server 2008 license or the default. Because, as others have mentioned, the vast majority of large webhosts or Linux users "roll their own free distro" or purchase an enterprise agreement from RH or Suse, they will never be counted. Microsoft always plays games with the numbers. They are playing a similar game with Windows 7 numbers - You can buy a Windows 7 upgrade for $99, which only gives you a single license, or you can buy a "family upgrade pack" for $99, which gives you 3 upgrade licenses. Guess which one allows them to count 3x the number of licenses sold? Right, and they made it so that the family pack can even upgrade pirated versions of XP (I know this because I used this to bring one of my home copies up to legit status). It's a genius marketing move because for basically $33 per computer they get all the pirate computers to become fully legit, counted installs of Windows. Never mind all the double-counting and triple-counting of licenses - MS has always been king at this. They force Dell/HP to bundle a license of Windows 7 with every computer sold knowing that corporations have Volume License Keys and wipe and reinstall Windows with their corp version. 2 copies of Windows sold for every physical computer. What I would really like to see are the numbers of Windows computers receiving updates. That would be a legitimate number.