When Valve will port all their games the number will increase significantly. Also the support from AMD and NVIDIA must be more Linux oriented.

0.71% Ubuntu 12.10 64 bit 
0.38% Ubuntu 12.10         
0.31% Ubuntu 12.04.2 LTS 64 bit 
0.20% Ubuntu 12.04.2 LTS
0.17% Linux Mint 14 Nadia 64 bit
0.14% Linux 64 bit
0.11% Ubuntu 12.04.1 LTS 64 bit
0.06% Ubuntu 12.04.1 LTS
0.05% Linux Mint 14 Nadia
0.05% Arch Linux 64 bit
0.04% Linux Mint 13 Maya 64 bit
0.03% Debian GNU/Linux 7.0 (wheezy) 64 bit
0.03% Fedora release 18 (Spherical Cow) 64 bit
0.03% openSUSE 12.2 (x86_64) 64 bit
0.02% Ubuntu Raring Ringtail (development branch) 64 bit
0.02% Linux
0.02% Linux Mint 13 Maya
0.01% Gentoo Base System release 2.1 64 bit
0.01% Fedora release 17 (Beefy Miracle) 64 bit
0.01% elementary OS Luna 64 bit
0.01% Ubuntu 12.04 LTS
0.01% Debian GNU/Linux 7.0 (wheezy)
0.01% Ubuntu Raring Ringtail (development branch)
0.01% Ubuntu 12.04 LTS 64 bit
0.01% Gentoo Base System release 2.2 64 bit
0.01% Arch Linux
0.01% openSUSE 12.2 (i586)
0.00% Linux 3.2 64 bit
0.00% Manjaro Linux 64 bit
0.00% Linux 3.2
0.00% elementary OS Luna
0.00% Gentoo 64 bit
0.00% Ubuntu-Secure-Remix 12.10 30nov2012 64 bit
0.00% Chakra Linux 64 bit
0.00% Fedora release 18 (Spherical Cow)
0.00% Chakra" 64 bit
0.00% Fedora release 17 (Beefy Miracle)
0.00% Zorin OS 6 64 bit
0.00% Debian GNU/Linux testing (wheezy) 64 bit
0.00% Sabayon Linux amd64 11 64 bit
0.00% Manjaro Linux
0.00% Linux Mint 12 Lisa 64 bit

that is a lot of distro's to 2,45%

anyways when do they take these ?  as soon as you start it or you need to have it running at a certain time ?  since they still not fixed the tray icon on kde4 (not on my desktop anyways) I only run it when I need it

It's just at a random time when you are logged in.

It happens at the start of the month (though it's possible that users selected to participate who don't log in until later in the month may not see the prompt until then). Users are selected at random to participate. The sample size is unknown, and there have previously been bugs with the sampling process.

I've attempted to keep track of details in the Steam forums.

What distro is called Linux? Or is this referring to older Linux distributions in general based on Kernel version? I am curious why they'd include stats for distributions that are practically at 0.00%...

I wonder if there's a future where we'll see 20-40% of the desktop market owned by Linux distributions, in a time where desktops are still important that is.

If you look at Steam.sh, you can see the methods with which Steam grabs this information. When results were published at the beginning of the month, some of us within the SteamLUG community were able to identify that Arch users without lsb-release installed were showing up as "Linux 64 bit" (other distros may show up differently).

It's also pretty easy to put your own text in places where Steam will pick it up. It'll be interested to see if/how Valve go about preventing people from submitting silly distro names.

If my math is correct, all of the Ubuntus together (not counting Mints or any other derivs) come to 1.82%, which is 72.8% of the Linux users.  While I DEFINITELY agree that Valve should be trying to be as cross-distro as possible, these numbers are the reason why they focus on Ubuntu so much (unless you believe people are using Ubuntu with Steam b/c it has the best support).

Wow, looking pretty good so far. I'd imaging that these numbers will keep increasing slowly month by month, and it'll be really interesting to see where they go. If I'm hopeful, I'd imagine they will grow very slowly each month, with a slight bump whenever a high profile game is released on Linux.

Hey Cheese, what do you think about a Steam user share visualization for Linux? It might be interesting to watch from here on out.

How can they count OpenSUSE user ? OpenSUSE is not in the UserAgent !