This has been an amazing turn of events. Until an year or two ago, Valve Inc. was a company popular among Windows users primarily. A great number of Linux users maintained a dual boot system with Windows on it because of the lack of good games for Linux, especially those from the Steam library. There were rumors like these as early as in 2010, but nothing concrete. Things are the exact opposite now. Valve not only released its official Steam for Linux client, they are now even promoting it actively to non-Linux users too through their website, encouraging its users to try Ubuntu 12.04 LTS!
Truly an Amazing Turn of Events
Just visit http://store.steampowered.com/about page and you will see Valve's new promotional item. Not all games available for Windows hasn't been ported to Linux yet, but even then, this is an amazingly brilliant start. Things like these just might be the kind of traction Linux requires to go mainstream in the Windows dominated laptop and PC market.
[thanks to our reader kevin for the info]