GNU/Linux: Not Just DIY Computing
There was a time, not long ago, when GNU/Linux was only for hardcore geeks. Whatever distro one used (or made from scratch), a fair amount of programming knowledge was required. Linux was almost exclusively a "back end" server system. Of course it's still very popular for servers, but there are more and more desktop distros available that are ready "off the shelf."
When someone buys a computer with Windows pre-installed there isn't much to do. Just turn the computer on, adjust a few settings and that's it. If you have to do the installation yourself, that's somewhat more of a pain. In my experience it can take a couple of hours to install and then register Windows. By comparison, Ubuntu, a Linux distro, can be installed in minutes.
You won't hear much about Linux in general or Ubuntu in particular in computer stores. Though Windows and Mac fanboys would have you believe that's because Linux "isn't ready" for the popular market, I really don't think that's the case.