It’s not so much the technology behind Linux that’s fascinating – it’s what Linux has enabled in its 20 year lifespan. Linux has grown from a hobby OS that ran only on Intel-based 386 computers to powering everything from the smallest embedded devices to most of the world’s supercomputers. While Linux has largely failed to make a dent on the desktop, where Apple shines, it’s made amazing progress everywhere else.
If you’re reading this site, you’re using Linux indirectly. It’s no exaggeration to say that the Web as it is today would not exist if it weren’t for Linux. The rapid explosion of Web sites and Web businesses were made possible largely by Linux. Not because Linux was technically superior, but because it was freely available and open to modification. Many of the largest and most influential businesses of the last decade wouldn’t have been viable if it weren’t for Linux and the rest of the free software stack.

Use Facebook, Twitter, or Google? Again, all of those companies depend heavily on Linux. If you buy stuff from Amazon, bid on auctions on eBay, or watch a movie using Netflix streaming – you’re using Linux. Linux also powers control systems in nuclear submarines. It’s hard to imagine the rise of big data or cloud computing without Linux. Amazon Web Services? Linux. Rackspace Cloud? Linux. Google App Engine? You get the idea.
On the consumer side, life would look a lot different without Linux as well. If you use an Android phone, or a Kindle eBook reader, you’re using Linux. It also powers the Roku Internet TV devices. It’s also being used for In-Vehicle-Infotainment (IVI) systems, and countless other devices.
http://readwrite.com/2011/08/25/as-steve-jobs-steps-down-linux/